Leading-What's the Problem?

[ColColt]

I didn't have a very lucrative trip to the range today and was a bit disappointed...not so much in the shooting but in leading. My Ruger GP100 has a throat diameter of .358" per the pin gauges. The .3585 gauge will not fit so it's pretty much right on at .358". I size the boolits accordingly and lube with BAC.

My loads were from a mold I got from Mountain Molds that pretty much mimics the 358429 boolit with some minor changes. It has three equal bands and little shorter nose than the 358429. Loads today consisted of the below...

9 gr HS-6 with ww's + 3 oz tin
9 gr HS-6 with 50/50 lead-Linotype
7.5 gr Universal with ww's + 3 oz tin

Unfortunately, I left my targets at the range where I had scribbled notes on each target and am recalling this from memory. One of the two loads above leaded from just where the rifling starts to the muzzle...not much at the muzzle but a little more at the forcing cone right ahead of the rifling.

The other load only leaded a little just ahead of the forcing cone for about an inch as you get into the rifling. None of these loads actually leaded the forcing cone itself-just from the rifling on.

What I can't figure is why any leading at all. The boolits fit the throat and either the ww's + tin or the 50/50 alloy shouldn't have mattered since there was a proper fit of boolit to throat.

Last week I had my M29 out for a spin at the range and was using the Lyman 429421 and a custom boolit with the same weight behind 11 gr of HS-6 in both ww's +tin and my 50/50 alloy. There was zero leading. None at the muzzle and none at the forcing cone. So, what's with the Ruger? Boolits fit both guns and alloys are the same, powder is the same.

[Mohavedog]

Hello ColColt,
Sounds like the Ruger bbl is oversize for the boolit dia. If you slug the bbl you will probably find it larger than the 29 bbl. Remedy would be to ream the cylinder throats to .001 or .0015 over bbl groove dia and size the boolits to the new throat dia. This may mean that rounds made for the Ruger may not chamber in the 29 without reaming it also.
I don't post much but someone will come along and add more info......Mohavedog

edit: for years I confuse "forcing cone" with "throat". I always thought that the throat was in the cylinder and forcing cone was in the bbl. Am I wrong on this?

[Gswain]

What does your barrel slug at?

[geargnasher]

Ever hear of the term "Thread choke"?

Rugers are famous for it. Due to a Ruger innovation that enables sorting and matching barrels and frames into three groups, the amount of barrel torque varies quite a bit, and if you have a gun with the torque at the ragged edge of needing to go on a frame with the threads in the next clocking position, then the forcing cone area gets crushed when the barrel is torqued, and the resulting restriction will cause leading if your boolits are too hard for the pressure you're putting behind them. I'd say clean the gun, stuff some 2400 in the cases and work right up to book max, see if the leading goes away. Clean between strings. HS6 might do it, I've done a lot of shooting with my buddy's using the Lyman 358665? and HS6, my notes are at home but I was using more powder I'm fairly certain. I fixed the thread restriction in his, polished the machine marks out of the forcing cone, reamed and polished the cylinder throats to .3583", and it quit leading the barrel with .358" air-cooled WW boolits.

If you want to measure thread choke, cast some boolits out of pure lead. Clean and lightly oil the bore. Drive one through from the muzzle all the way with a brass rod. Then, drive another one in from the muzzle, but this time STOP about an inch shy of the frame. Cut some small sections of 5/15" birch dowels that will fit through the frame opening, place a flat bar through the frame near the recoil shield so you can press the dowel through the bore from the breech end. When the bar touches the barrel, insert another section of dowel, push it through, and keep stacking them until the slug comes back out the muzzle. If this second slug, which did NOT go through the frame area of the barrel, is LARGER than the one pushed all the way through, then you have thread choke. Anything over .0005" (five ten-thou) will likely cause leading unless you tweak your loads to maintain obturation, and that requires softer lead or at least pressures well above the yield strength of the alloy.

Gear

[ColColt]

Gear-I never did slug the bore but mostly went by the throat diameter to size the boolits. Nope-never heard of thread choke before but I have read about the "squeeze" at the barrel/frame junction. I don't have a chrony so, I don't really know the velocity of the loads I was using. I can't image them being over 1100-1200 fps, however and either a BHN 12 or 15 should have obturated with either. Not having QUICKLoad either I don't know the chamber pressure for sure but, it's definitely lower than the SAMMI specs on the 357 of 35,000 psi.

One part I've noticed is that the forcing cone does have the familiar circles around it from machining but there's no lead in the forcing cone-just directly ahead where the rifling begins.


If this second slug, which did NOT go through the frame area of the barrel, is LARGER than the one pushed all the way through, then you have thread choke.

What can I do about it if that's the case?

[Iron Mike Golf]

+1 on gear's remarks. Thread choke caused leading just as ColColt described in my RH.

[357 Voodoo]

ColColt

Here is a good link that will explan how to check for and fix the thread choke follow this link (http://www.gunblast.com/FerminGarza-Firelapping.htm)

[cbrick]

Yep, Gear is right.

Slugging the bore of a revolver is as important as slugging (or pin gauges if you prefer) the throats and there is but one reason to do it . . . To know that the groove diameter either matches or is smaller than throat diameter. You were correct to size to throat diameter but you also need to know the groove diameter to know if the match is correct.

If there is a barrel frame restriction Gear's description of checking this is spot on. If there is a barrel frame restriction it acts just like a sizing die reducing the bullet diameter as it passes through, from there until the muzzle it is just the same as if you had originally sized the bullet too small and there is blow by.

The common cure for a barrel frame restriction is fire lapping, this is much like finger nails on a blackboard to me but sometimes needed and it does work.

Rick

[ColColt]

I pushed a soft boolit down the bore that dropped from the mold was .360". Passed all the way through it read .357"-right on. So the .358" I use for the throats is perfect. However, perhaps my imagination but it seemed like it as a little harder to push when the boolit got to about where the frame is. That's as far as I've gotten as I don't have any small dowel rods I can cut other than the one I used to drive the boolit down the bore.

I don't have pin gauges small enough to fit the bore(.3570" smallest) but that was a good article and made sense using the gauges and I would have tried that but don't have an entire set of gauges.

[462]

Putting an 11-degree cut on the forcing cone, will eliminate some leading, too, though your barrel restriction is the major culprit.

[btroj]

You have a good candidate for fire lapping. It sure helped my GP100 stop leading.

Gear- when you say Ruger sorts and matches barrels and frames into 3 groups I need to know this- do they do this to help reduce this problem or do they do it to maximize thread choke? Some times I sure wonder.

[ColColt]

Two questions about fire lapping. I've never done it before so bare with me. Will that not create a tapered barrel and secondly, will it not increase the diameter of the throats?

I've read somewhere and can never recall which is the case but, it seems shooting a soft boolittoo fast can lead at the forcing cone or a too hard a boolit driven too slow will lead at the forcing cone...can't recall which is which but cold this possible be the case instead of a constricted barrel?

[Larry Gibson]

ColColt

I'd switch powders before I got wrapped around the axle on anything else. Is 9 gr HS6 a proven load in another .357? I'd try a couple of the older proven powders such as 2400, 4227, H110 or Unique. Just a suggestion.

Larry Gibson

[ColColt]

Larry-Loads for 170 gr bullets are not numerous. Hodgdon's online data indicated a max charge of 9.2 gr of HS-6 with the Sierra 170 gr JHC and that's basically where I got my load. There are not pressure signs and it's an accurate load but just creates leading somewhat. It's not terrible and it's not abundant but shouldn't be there in light of a good match between throat and barrel groove diameter.

[btroj]

It can increase throat diameter but I haven't had that trouble. I think it is Gear that mentioned using a atop or something to lightly coat the forcing cone and just shoot regular , light loads with cast.
I have just done a normal fire lapping in mine. Just don't over do it. I would use 320 grit Clover and real soft bullets with a light charge of a powder like Trailboss. Give it 24 or so then clean well and shoot some normal loads. You can always take more off, it is darn tough to put it back on. You could also shoot 2 to 500 jacketed loads throughout it, lapping is just accelerated wear after all.

Larry does have a good point. This may well be something that can be eliminated through loading or a different alloy. It all depends upon your mindset I suppose.

[geargnasher]

ColColt, excellent tips here. Remember, like Larry and I pointed out, try a different powder. Work up a new load, cleaning between strings, see if you get to the point that it starts to bump-up the boolit and keep the seal past the restriction and stop the leading.

What you read about soft/hard fast/slow was right, if a soft boolit hits the forcing cone too fast, but with not enough pressure behind it still when it enters, as with super-fast powders, it can "skid" into the rifling bad enough to open trailing-edge leaks on the boolit, and it will lead to buggary. If it's launched slowly, with a powder that makes peak pressure just about the time the boolit base clears the cylinder (like HS6 or 2400 if you get the right charge worked out), it will take the rifling better and have enough pressure on the base still to rivet to obturate (seal) the bore and not lead. If the boolit is too hard, the only reason it will lead is if it's undersized or if there is a restriction causing a leak after the boolit passes it, be it the cylinder throats, forcing cone, roll-embossed encylopedia on the side of the barrel, front sight soldering, you name it. Hard boolits that fit and the smallest point of the boolit's path located at the muzzle create a condition that, in my experience, usually won't lead a revolver.

The reason I mentioned thread choke and how to check for it is to make you AWARE of the problem, and give you a "specification" that you could use as a judgement call as to whether you can fix it with simply working on the load, or if it's too bad and needs mechanical alteration.

I fixed my Ruger New Vaquero with a .4525" chucking reamer, some 400-grit sandpaper, some 320 Clover compound, some Lee 255-grain boolits cast from 30:1, and three grains of Red Dot and a half-grain of Dacron. The idea to coat just the barrel with the Clover wasn't mine, someone else here mentioned it in passing once, but it works. I took a Q-tip and swabbed just the forcing cone and first inch of the barrel with the paste, then fired the above boolits lubed with 45/45/10 through it, that way the throats didn't get messed up. When I got rid of the choke (about 30 rounds), I reamed the cylinders using the chucking reamer and some painter's tape for a guide bushing in the cylinders, polished with 400 emery, oil, and a dowel rod, and polished the forcing cone with a lead lap made from a filed-down Lyman 457132. Keep in mind, I tried everything I could think of loadwise to get the leading to stop and the thread choke was just too severe.

So now you know the rest of the story!

Gear

[357 Voodoo]

ColColt

I was looking at a few of my notes on hs-6 and it was real hit and miss with it. It seemed to have a very very narrow window in which it would perform with accuracy and no leading. i would recommend switching powders use one of the ones larry suggested.

[357shooter]

Powder choice is important and may help with the leading. Maybe enough to be satisfied with the results. If it's caused by a "rough" spot at the constriction that still leads, then fire lapping may resolve it.

In my own experience I've only fire lapped 2 barrels, both times it worked. Accuracy was improved, and leading was eliminated. Both times I used the 600 grit compound only, for 21 rounds. That was all that was needed. The 220 and 320 grit compound is still on hand in case it's needed at some time on a new gun. There was no problem with the throats being opened up. With a 7 round capacity, each throat was lapped 3 times. The barrel was lapped the full 21 times, receiving most of the treatment.

Maybe the results would have even been better had I used all the compounds. But I was skeptical and didn't want to chance it. Until you try it yourself, it's tough to appreciate how well it works. At least it did for my guns.

[Bret4207]

I didn't have a very lucrative trip to the range today and was a bit disappointed...not so much in the shooting but in leading. My Ruger GP100 has a throat diameter of .358" per the pin gauges. The .3585 gauge will not fit so it's pretty much right on at .358". I size the boolits accordingly and lube with BAC.

My loads were from a mold I got from Mountain Molds that pretty much mimics the 358429 boolit with some minor changes. It has three equal bands and little shorter nose than the 358429. Loads today consisted of the below...

9 gr HS-6 with ww's + 3 oz tin
9 gr HS-6 with 50/50 lead-Linotype
7.5 gr Universal with ww's + 3 oz tin

Unfortunately, I left my targets at the range where I had scribbled notes on each target and am recalling this from memory. One of the two loads above leaded from just where the rifling starts to the muzzle...not much at the muzzle but a little more at the forcing cone right ahead of the rifling.

The other load only leaded a little just ahead of the forcing cone for about an inch as you get into the rifling. None of these loads actually leaded the forcing cone itself-just from the rifling on.

What I can't figure is why any leading at all. The boolits fit the throat and either the ww's + tin or the 50/50 alloy shouldn't have mattered since there was a proper fit of boolit to throat.

Last week I had my M29 out for a spin at the range and was using the Lyman 429421 and a custom boolit with the same weight behind 11 gr of HS-6 in both ww's +tin and my 50/50 alloy. There was zero leading. None at the muzzle and none at the forcing cone. So, what's with the Ruger? Boolits fit both guns and alloys are the same, powder is the same.

No, you don't have proper fit. And you can't make the assumption that what is "proper fit" in one gun with one load is going to be correct for another gun of a completely different make and caliber. Your thinking static fit and you should be close there, but your dynamic fit is way off, maybe by the frame crush or maybe by your powder choice or maybe by something else. Took me a long, long time to see that there's more to fit than just size.

[ColColt]

I don't recall why I got turned on to HS-6. Maybe it was due to looking for a better, cleaner powder than Unique and yet not as slow as 2400. Maybe someone else talked about it and it all sounded good. Pressure levels to velocity seemed good. Accuracy has been good but the leading problem has persisted. Universal fit the bill but, it doesn't meter well in my powder measure(like Unique) but is an accurate powder for me in the 357 as well as 44. For both cartridges I like a velocity level around 950-1200 fps. 2400 is a superb powder and I have that in stock but to me it's primarily for magnum loads with a near full case. I didn't want to shoot full house(or close) magnum loads all the time due to the wear and tear on the gun and myself. Moreover, I'm not into recoil like 30 years ago. I have used 13.5 gr of 2400 and it did very good but more recoil than I care to experience for 50 rounds.


I've got probably half a dozen or so different powder from Power Pistol to 2400 and I haven't tried the former in this caliber as yet. AA#5 may do well and I'll work up a load with that. H110 and 296 are not my cup of tea as you can't load either down and they're both full house magnum loads. Being primarily a paper puncher and not a hunter, I don't need 1400+ fps loads. They're fun to shoot periodically but not on a weekly basis for me.

Since the boolits are not undersized and I don't think I'm pushing them too fast with either HS-6 nor Universal for the alloys used, I can only surmise that perhaps the real culprit here may very well be the restriction at the frame. Never having fire lapped a barrel before it sounds like a real pain to do but, as with anything, something new and different always leaves you feeling a bit intimidated and unsure about the process....me doing it, that is, not that it hasn't worked numerous times for others.

I think I need to get another dowel rod and use the instructions gear gave before actually attempting this process to assure myself that indeed this is the problem. Having slugged the bore yesterday to check the groove diameter, I couldn't really tell if there was a restriction at the frame or not. I don't think the lube is part of the problem in this quotient in that I see small specks of it on the target and that tells me it's still making it out of the barrel with the boolit. I suppose it may behoove me to try that 13.5 gr of 2400 again and look closely as to whether it does the same thing as my other loads. Maybe even try some AA#5 with the same boolits.

In the event it's proven that there is a restriction, what is the consensus on the product from NECO? I ran across this while looking for QUICKLoad yesterday evening. BTW-heartfelt thanks for all the replies and instructions as to the possible cause of my current problem.

http://www.neconos.com/details2.htm

[cbrick]

I think I need to get another dowel rod and use the instructions gear gave before actually attempting this process to assure myself that indeed this is the problem.

Absolutely!

Always be positive about the problem BEFORE doing anything that will alter the firearm. I thought my 624 44 Spl was going to need firelapping because of a barrel/frame restriction but before doing so a closer examination showed that the leading started on the forcing cone and spread down past the barrel threads. Looking even closer I found that the leading was starting in the cylinder, blowing out onto the forcing cone and then spreading into the bore.

I was firing 50-100 rounds and leading was terrible. After firing only about 10 rounds and inspecting for the leading showed that the leading was mostly in the cylinder with just a bit blowing out onto the forcing cone. Continued shooting continued the leading into the bore to just past the barrel/frame causing me to believe it was a barrel/frame restriction.

The cure was a bullet that was long enough to have the front driving band inside the throat when chambered. The shorter bullets were laying at an angle in the chamber, when fired the the edge of the front driving band hit the edge of the throat and shaved lead, more shooting and more leading until it was down into the bore.

Mighty happy I didn't jump to my first conclusion and of a barrel/frame restriction and fire lap it, it didn't need it. I can shoot that gun all day now with zero leading and the cure was as simple as could be.

By all means measure for a barrel restriction before altering the firearm.

Rick

[geargnasher]

I don't recall why I got turned on to HS-6. Maybe it was due to looking for a better, cleaner powder than Unique and yet not as slow as 2400. Maybe someone else talked about it and it all sounded good. Pressure levels to velocity seemed good. Accuracy has been good but the leading problem has persisted. Universal fit the bill but, it doesn't meter well in my powder measure(like Unique) but is an accurate powder for me in the 357 as well as 44. For both cartridges I like a velocity level around 950-1200 fps. Col, may I suggest a new line of thinking here? You said "I like". Perhaps you should consider more what the gun likes, because it's talking to you right now and telling you that you should change something. I think you have thread choke, and possibly an unbalanced load (alloy/pressure/pressure-time curve not balanced). You might be able to work around it with a load change, but it will likely require hotter loads to make the boolit expand to keep the seal late in the game (after it passes the frame restriction), and this is a lot to ask from a light load. 2400 is a superb powder and I have that in stock but to me it's primarily for magnum loads with a near full case. It is, as it needs high pressure for a clean and consistent burn. I didn't want to shoot full house(or close) magnum loads all the time due to the wear and tear on the gun and myself. Understood. You might have to do some dimensional corrections on the gun to get it to work well, though. Moreover, I'm not into recoil like 30 years ago. I have used 13.5 gr of 2400 and it did very good but more recoil than I care to experience for 50 rounds. Why don't you go load up 25 like that, clean the gun really well, and go shoot them just to see if the leading stops? If it does, then you'll have to alter tack considerably to get it to work within the power levels you desire.


I've got probably half a dozen or so different powder from Power Pistol to 2400 and I haven't tried the former in this caliber as yet. AA#5 may do well and I'll work up a load with that. Good idea. H110 and 296 are not my cup of tea as you can't load either down and they're both full house magnum loads. Being primarily a paper puncher and not a hunter, I don't need 1400+ fps loads. They're fun to shoot periodically but not on a weekly basis for me.

Since the boolits are not undersized Never make that assumption. See Bret's post above about DYNAMIC FIT. The boolit might fit like a glove until you fire it, then it goes to hell somewhere down the pipe. and I don't think I'm pushing them too fast with either HS-6 nor Universal for the alloys used, I can only surmise that perhaps the real culprit here may very well be the restriction at the frame. Very possible. Never having fire lapped a barrel before it sounds like a real pain to do but, as with anything, something new and different always leaves you feeling a bit intimidated and unsure about the process....me doing it, that is, not that it hasn't worked numerous times for others. Take the slug measurements like I suggested, then you'll know what you're dealing with. If you have a significant restriction, it's easy as pie to load up half a box of popgun loads, swing out the cylinder and swab the inside of the barrel right in the frame are with 320 Clover Compound using a Q-tip, fire one, swab, fire one, swab, repeat about 15 times, clean the barrel and reslug all the way through to check your progress against the first all-the-way-through slug's measurements.

I think I need to get another dowel rod and use the instructions gear gave before actually attempting this process to assure myself that indeed this is the problem. Having slugged the bore yesterday to check the groove diameter, I couldn't really tell if there was a restriction at the frame or not. I don't think the lube is part of the problem in this quotient in that I see small specks of it on the target and that tells me it's still making it out of the barrel with the boolit. I suppose it may behoove me to try that 13.5 gr of 2400 again and look closely as to whether it does the same thing as my other loads. Maybe even try some AA#5 with the same boolits.

In the event it's proven that there is a restriction, what is the consensus on the product from NECO? I ran across this while looking for QUICKLoad yesterday evening. BTW-heartfelt thanks for all the replies and instructions as to the possible cause of my current problem.

http://www.neconos.com/details2.htm

IF it proves necessary, just get some Clover brand valve-grinding compound from an autoparts store or automotive machine shop, use the coarse stuff, then finer to finish if you think you need it. It's important not to be intimitated by the size of the coarse grit, the abrasive crushes quickly into much finer stuff under pressure, and what's 150 or 320 at the frame will be 1200 at the muzzle. Ruger steel is TOUGH. Pay attention, but don't be "skeered". Thread choke may not even be your problem, or if it is, balancing the load better with AA5 and softer alloy might be all it takes. But I'd measure anyway so you know where you stand.

Gear

[btroj]

A different powder may well give you no leading and keep you in the velocity window you like. That is a velocity which can easily be met with so many powders.
A different pressure/time curve with a slightly softer alloy may allow the bullet to keep it's fit even with thread choke.
I suppose the first question we should have asked is this- does the leading seem to affect accuracy? Are the first 6 loads more accurate than those after say 50 rounds? I don't worry about leading if it doesn't seem to hurt anything.

[ColColt]

I was getting ready to drive another boolit down the bore shy of getting to the frame and back it out with the dowel rods and got to thinking, if the one I've already driven through the entire length of the barrel came out as .357"(groove diameter) I wouldn't think the one I only drove up to the frame would be more than that or am I missing something? I measured that boolit in several places all the way around twice to be sure I wasn't measuring wrong. My mic won't measure as small as .0001 but I can measure to .0005 by interpolating between numbers and the little marks.


Looking even closer I found that the leading was starting in the cylinder, blowing out onto the forcing cone and then spreading into the bore.

I didn't mention that I also had some leading in the throats-not sure why that is as the boolits match in size to the throats and I'm using ww's plus a tad of tin. Probably the throats are rough. Rugers are notorious for a less than perfect bore/cylinder in that respect. Even though the forcing cone has tool marks, there was no lead there-just from ahead of it into the rifling.

I wish I could remember the last time I shot the 2400 loads and if there was leading. Usually, I jot down notes on each target about what the load was, the BHN I used, how many shots, powder used, if leading was present and where, etc. That way I can bring them home and study the results. I clean the bore and cylinder between different loads so the preceding one won't influence the next test. I'm going to load 25 of the 2400 loads I've shot before and pay close attention to what the results are. I'm also going to try 8.5 gr of AA#5 with the 158 gr boolit since I couldn't find that powder listed for the 170 gr boolit I so like.

Oddly enough, no one around here sells the Clover brand of compound. I've tried Auto Zone, NAPA and another local dealer and no one has it-just Permatex in a tube and nothing's noted about what grit is on the packaging. I'll have to get if off the Internet. However, I need to follow through with checking a little further with this before I go with that. It still makes me a little "skeered" doing the fire lapping.:)


I suppose the first question we should have asked is this- does the leading seem to affect accuracy? Are the first 6 loads more accurate than those after say 50 rounds? I don't worry about leading if it doesn't seem to hurt anything.

It doesn't seem to affect the accuracy. Groups are still decent to me(less than 2" if I do my part). Usually I don't fire more than 25 of a given load, clean and fire the next 15-25 since I'm still running tests with this revolver.

[Bret4207]

Re-read Gears #22 post a couple times, he covers the dynamic fit issue pretty well.

[ColColt]

I finally got those measurements. What a pain to get that boolit out with sections of dowel rods!! Don't want to do that anytime soon. I guess I'm getting weak trying to push it through but at any rate, both measured the same at .357" so apparently, restriction isn't the cause. I took measurements up and down on different bands all the way around both of them several times to be sure I wasn't off in my assessment.

I suppose now it must be a matter of load choosing. It still puzzles me a bit why I had no problems with the right size boolit in my 44. I know they're different is many respects but with my two favorite powders, HS-6 and Universal, there was no lead in the throats, forcing cone, or muzzle on the 44. I sort of wish I had found .001" difference between the push through and the one I stopped at about and inch and a half shy of getting to the frame on the Ruger. Then, I'd know what I'd have to do but; that doesn't seem to be the case so, I guess it's over for HS-6 with this 357 and onward to something else-starting with 2400.

There's another possibility. My mic doesn't measure .0001" so it could be that last boolit is actually .0001-.0002" larger. It's actually hard for me to tell.

[462]

Glad to hear that it doesn't apperar to be a barrel constriction. However, the purchase of a better micrometer should be at the top of your priority list. (Seems like tools and equipment purchases are never ending. I just bought a third set of .38/357 dies, and will be having some custom M-die plugs made.)

This could become an invaluable thread, in that ColColt didn't go directly to fire-lapping. Instead, he re-slugged his barrel, and will be trying different loads with different powders. In other words, when a problem presents itself, start with the basics. After they have been exhausted, and the problem still persists, then move on to a more advanced approach.

[357 Voodoo]

This could become an invaluable thread, in that ColColt didn't go directly to fire-lapping. Instead, he re-slugged his barrel, and will be trying different loads with different powders. In other words, when a problem presents itself, start with the basics. After they have been exhausted, and the problem still persists, then move on to a more advanced approach.
This right here is what more and more people need to remember and make one change at a time.

Colcolt keep plugging away you will succeed a lot of good advice has been given to steer you in the right direction.

If your measurements are within .0001-.0003 or there abouts a different powder that maintains the dynamic fit of the boolit will help.

[geargnasher]

ColColt, I was making the recommendation for 2400 load only because it is a good way to deal with leading caused by a restriction. If you don't have a measurable restriction, and your cylinder throats are slightly larger than the groove dimension (which they appear to be), then I think your gun is good to go, and you should proceed with load development in a direction of something more to your liking.

What I'm thinking now is that you are having bigtime blowby right when the boolit base clears the case mouth, or maybe before it even moves. Sometimes (maybe always) cases expand before the boolit moves and lets a jet of gas go around the boolit and out the cylinder ahead of it before it gets moving. If you can figure out a way to seat the booit further out into the cylinder, or try a design with a longer front band, maybe this would help. Also, if you can size .359" and still chamber the cartridges it would be a big help. The goal here is to prevent gas blowby the whole way through the gun, and as the boolit goes through the cylinder throat and into the barrel gas leakage will erode the boolit and can cause leading.

The Ruger forcing cones sometimes look like they were cut with a rusty step-drill and lead actually rubs off on the rough machine marks, then gets smeared down the barrel on subsequent shots.

Lots of things to try here, but I'd focus on your velocity goal, and use a medium alloy like straight clip-on wheel weights and Universal/Unique (or equivalent), and play with the alloy until you get to a happy place. FYI, soft alloy like straight stick-on weights at about 7 bhn will shoot lights out with my buddy's 4" SS GP100 using 2.7 grains of Clays pushing a 158 grain RFN at about 750 fps.

Gear

[Bret4207]

I suppose now it must be a matter of load choosing. It still puzzles me a bit why I had no problems with the right size boolit in my 44. I know they're different is many respects but with my two favorite powders, HS-6 and Universal, there was no lead in the throats, forcing cone, or muzzle on the 44. Two different calibers, manufacturers, chamber reamers, dimensions are all over he place between the 2. Plus, 2 entirely differently boolit weights/sizes. shapes, etc. Apples and oranges, relatively speaking. I sort of wish I had found .001" difference between the push through and the one I stopped at about and inch and a half shy of getting to the frame on the Ruger. Then, I'd know what I'd have to do but; that doesn't seem to be the case so, I guess it's over for HS-6 with this 357 and onward to something else-starting with 2400.

There's another possibility. My mic doesn't measure .0001" so it could be that last boolit is actually .0001-.0002" larger. It's actually hard for me to tell.

I'm repeating myself, but each gun is a law unto itself. Yes, fit comes first but every gun will want something a little different to achieve max performance. Some guns are simply a lot more cast friendly than others, some cartridges too. You'll even find the occasional gun/load combo that like it's boolits right at groove size.

We're it me, first thing I'd do is go with an established load/boolit combo and play with size followed by seating depth and crimp.

[ColColt]

A better mic indeed. I checked the diameter of a 45 cal boolit(.451") to be sure my mic was right on before proceeding to measure the two boolits I used to check for the restriction. I would feel better if I had another mic, however.

I'm still kicking myself that I left my targets/notes at the range but I'm going to go by there tomorrow and pick them up. I nearly got home and discovered I'd left them and once home I called for them to just put them back for me-hopefully, they did. I was using three different boolits at the range Friday. One was the 358429, a custom mold by Mountain molds and the Lee 358-158-RN. I always seat right up to the crimp groove on all of them. The Lyman is a bit longer at the nose than the Mountain Mold but I can't imagine that making that much difference as for possible leading problems as the Lee is even shorter. All three give good accuracy with the powders I used which was the HS-6 and 5.5 gr Universal with the Lee boolits(358-158-RF). Also tried was 7.5 gr of HS-6 with the same Lee boolit. My notes on the target are a valuable aid so, I need to pick those up tomorrow. I can't trust memory to six different targets and notes.

I wish I could have taken a picture of what the inside of the area just ahead of the forcing cone looked like. It wasn't horrendous but, there was lead visible and in reflecting of what I saw with the bore light, it was primarily at 6:00-8:00 o'clock, but, I don't think the location matters.

I only have a .358" size die so I can't try .359" as most of the boolits that fall from the custom mold are around .361". If you think I ought to try .359" I can always order one from Lyman. That, of course, will be .002" over groove diameter. My .359" pin gauge will not go into the throats so, the boolit will probably just get swagged down.

I'm going to take a couple of different loads to the range next time and 2400 will be among them. Also, I'll use the 5.5 gr of Universal and 8.5 gr of AA#5 with the Lee boolit . I guess I'm still a little puzzled why a given powder would cause leading more than another given the same boolit in the same gun...guess I'm just thick headed in that respect. I'm not a great fan of the fast powders and like the medium burn powders best so Universal is about the fastest powder I use and mostly because it's a good substitute for Unique and meters better.

I think starting here with the different loads should be prioritized and if that fails to decrease the leading, perhaps I'll have to regroup and follow a different approach. I want to stress once again the thanks for you all giving me such great help and your time on this.

This is a shot of the 170 gr bullet I used at the range for my testing. The nose is somewhat shorter than the 358429 by about .010".

http://i180.photobucket.com/albums/x220/ColColt/Misc%20Stuff/_DEF3980.jpg

[geargnasher]

A better mic indeed. I checked the diameter of a 45 cal boolit(.451") to be sure my mic was right on before proceeding to measure the two boolits I used to check for the restriction. I would feel better if I had another mic, however. What do you have, a 0-1" micrometer, or 6"calipers? Big difference between a "Mic" and calipers. Even the cheapest, Chinese micrometer is better than a good pair of calipers.

I'm still kicking myself that I left my targets/notes at the range but I'm going to go by there tomorrow and pick them up. I nearly got home and discovered I'd left them and once home I called for them to just put them back for me-hopefully, they did. I was using three different boolits at the range Friday. One was the 358429, a custom mold by Mountain molds and the Lee 358-158-RN. I always seat right up to the crimp groove on all of them. The Lyman is a bit longer at the nose than the Mountain Mold but I can't imagine that making that much difference as for possible leading problems as the Lee is even shorter. I think you missed my point earlier. Cylinder throats are tapered, and have a "ball seat" like a rifle. The tapered part, just ahead of the chamber, allows a larger-that-throat-sized boolit to be chambered and fired. If the ball seat is deep, and the boolit has to "jump" before the major diameter of the nose or the first driving band hits it, than the boolit can get a crooked start, or gas can jet around it, causing lead to be blown ahead of the boolit. If you could use a larger boolit, or one with a longer nose band, then you might be able to prevent this, think of "seating to engrave" like you would in a rifle, getting a good support and seal for the boolit right as it is fired. All three give good accuracy with the powders I used which was the HS-6 and 5.5 gr Universal with the Lee boolits(358-158-RF). Also tried was 7.5 gr of HS-6 with the same Lee boolit. My notes on the target are a valuable aid so, I need to pick those up tomorrow. I can't trust memory to six different targets and notes.

I wish I could have taken a picture of what the inside of the area just ahead of the forcing cone looked like. It wasn't horrendous but, there was lead visible and in reflecting of what I saw with the bore light, it was primarily at 6:00-8:00 o'clock, but, I don't think the location matters. Why not? Don't you think that gives some indication of timing and cylinder/bore alignment?

I only have a .358" size die so I can't try .359" as most of the boolits that fall from the custom mold are around .361". If you think I ought to try .359" I can always order one from Lyman. That, of course, will be .002" over groove diameter. We really don't care about groove diameter in a revolver, only that it's smaller than she cylinder throats. .002 is fine. My .359" pin gauge will not go into the throats so, the boolit will probably just get swagged down. NOW you're getting the idea! Tapered cylinder throats allow an oversized boolit to be chambered. When fired, it is swaged down slighly, ensuring a leak-free, tight, straight fit as the boolit passes from the cylinder to the barrel. The tight, press fit here helps prevent the boolit lube from being ejected from the groove out the cylinder gap, and it can do it's job in the barrel. As the boolit enters the forcing cone, it gets guided and swaged again by the forcing cone,then into the rifling. Double swage-fit here. The objective is to keep pressure on the boolit as it transitions, so there is good obturation and minimal gas leakage. The only way to achieve this is interference fit. I really think you should try a bigger boolit. Try measuring the others designs as-cast and see if you have some in the .359" range. If they are smaller, Beagle the mold with one piece of tape and cast some more, then load up a dummy, seat and crimp in the groove, and see if it will chamber all the way in all the holes. Now, see if you can force a bare boolit through the cylinder throat with your thumb, should be doable but pretty tough, If this is the case, lube a few of them by smearing lube in the groove with your fingers, and see how they shoot. Or just get a .359" die, or hone out your .358" die. I'm trying to keep you from doing unnecessary and permanent mods to a $25 tool here, but in the end you might need a .3585" boolit, and honing your existing die might be the best solution, especially if you're only loading for this one gun.

I'm going to take a couple of different loads to the range next time and 2400 will be among them. Also, I'll use the 5.5 gr of Universal and 8.5 gr of AA#5 with the Lee boolit . I guess I'm still a little puzzled why a given powder would cause leading more than another given the same boolit in the same gun...guess I'm just thick headed in that respect. I'm not a great fan of the fast powders and like the medium burn powders best so Universal is about the fastest powder I use and mostly because it's a good substitute for Unique and meters better. Universal is good stuff, not as versatile as Unique overall, but great in pistols.

I think starting here with the different loads should be prioritized and if that fails to decrease the leading, perhaps I'll have to regroup and follow a different approach. I want to stress once again the thanks for you all giving me such great help and your time on this.

This is a shot of the 170 gr bullet I used at the range for my testing. The nose is somewhat shorter than the 358429 by about .010". The important part is how far does the MAJOR diameter reach out in front, in other words, how long is the bearing surface? You want the first band or base of the nose to reach into the cylinder throat ball seat if possible.

http://i180.photobucket.com/albums/x220/ColColt/Misc%20Stuff/_DEF3980.jpg


Hang in there, I think you have a fit issue now, we'll get to the bottom of this.

Gear

[ColColt]

Gear-I have a 1" mic-manual jobby, not a digital readout. I'm a bit confused as to what is meant by "ball seat". I take it to mean as you indicated the part that is right ahead of the tapered section of the throat.

The nose band of this boolit in the photo is actually longer than that of the 358429 mold. The Lyman mold's front band is .09 whereby the one in the photo is .100". The Lyman boolit from top to the drive band is right at .270" whereas the other one is .260".

Unfortunately, this mold pictured, as cast with ww's is .360-.361". The Lyman varies depending on where it's measured with the largest as cast being .358" at the base and smallest(drive band) being .356" so, no dice with using that one. It seems about all I can do is get a .359" die and size the .361" boolit down.

Now, the Lee mold(358-158-RF), as cast, measures at .359-.360" with a soft alloy I used at BHN 9.2 . It's about the closest one I have to actually being able to be used as is. I made up a dummy round and it will chamber with ease but the nose of the boolit that sticks out doesn't really offer any resistance because of the shape of the boolit in that, it's not a swc with a band ahead of the case mouth. I did try to fore one though the throat but no go with the thumb. As mentioned, it's .359-.360". I don't know how it would shoot at that size.


The important part is how far does the MAJOR diameter reach out in front, in other words, how long is the bearing surface? You want the first band or base of the nose to reach into the cylinder throat ball seat if possible.


This I don't know. If you mean does the bullet have to jump a said amount before the front band actually hits the "ball seat". I don't know if it's not already there or just shy of it.

[geargnasher]

Sorry about the confusing "ball seat" term. It's really a rifle term, the ball seat, leade, etc. is the part of the throat that transitions from the throat to the rifled part of the barrel. In a revolver, the cylinders have a similar tapered part, that's to what I was referring.

It sounds like the Lee boolit would work fine for experimental purposes as-cast, especially if its fairly soft. Hand-lube a few and try them over a medium-ish charge of Universal, I think you'll like the results. If you can shoot 20 of them with no leading and good accuracy, you might consider the .359" die.

Gear

[geargnasher]

This illustration from Accurate Molds' website might help my description:

http://www.accuratemolds.com/img/bulletNose.png

Gear

[ColColt]

Gear-That illustration does indeed help. I'll load that boolit with about 5 gr of Universal and see what happens. I've also loaded 25 with 13.5 gr of 2400 and will be watching that with keen anticipation as well.

Many thanks for all this information and spending part of your Sunday answering these problems. Hopefully, if the roofing guys don't come out next Friday I'll have a chance to go by the range then.

[Three44s]

I uneqivocally recommend the Beartooth book if even just for late night reading.

It's very inexpensive and a good resource.

Another book that may not get everything right everytime but is generally spot on in practice even if just a bit jaded in theory is the LEE 2nd edition. Here, Lee explains the strength of different alloys ........... it's also not expensive if you shop even just a little bit.

The next book I would never want to be without is an older load manual .... it's Hogdons #26 .... THERE ..... you find the HS-6 loads done right .... later Hodgons loads are way too hot and lead to leading except under optimum conditions.

ColColt correctly asked about a tapered bore .... yes, and that's what you want.

And if you did end up firelapping by ALL means get the Clover brand abrassive. Get it from Beartooth if necessary.

ME .... I have not fire lapped anything yet ........... I like having the book anyway! I understand the terminology and these discussions MUCH better .... an all around good "fog cutter"!

What I have done is work with HS-6 a LOT ........... someone mentioned a narrow range ..... I did not experience that but no matter .... find that range and then enjoy a very fine powder.

HS-6 meters LIKE SIN! Even if it opperates in a narrow range .... once you are there .... any powder measure worth .02 will keep you in the groove!

But CC mentioned using a load with it as a near maximum for a J-word bullet .... that's missing the point of where HS-6 works well with lead ... or any powder for that matter for in my experience the best pressure range would be more in the area of the low 20K to about 24,000 psi.

I would definitely try a slug that's longer to see if the seal upon firing is an issue ...... then look at your forcing cone.

Third, my pet trick .... USP or JB bore paste and use it during each cleaning until major leading dissipates. I also use a product called CorrosionX and I dry patch it out after a cleaning session. All of this mildly polishes the cylinder and bore and then the CorrosionX seasons the internals much like seasoning a frying pan to not stick.

Don't think that you have to run 2400 at the top end ........... you mentioned 13.5 gr ..... it's way more flexible than that on the down side of that charge .......... I have run it very successfully as low as 17.5 gr. in a 44 mag but did better switching to mag primers as I dropped below around 18 gr. (I use standard primers at and above 18 or 18.5)


Three 44s

[Bret4207]

Col Colt- "I guess I'm still a little puzzled why a given powder would cause leading more than another given the same boolit in the same gun...guess I'm just thick headed in that respect."

Try it this way- each powder has a different pressure curve, it does different things to the boolit, just as increasing or decreasing a powder charge with the same powder alters the pressure curve. That's a big part of your dynamic fit. An altered pressure curve is offering the possibility of leading or not leading when it causes a different reaction to the boolit on ignition. One powder charge might take a slightly undersized boolit and cause it to obturate or "bump up" enough to properly fill the throat and grooves. Another might might cause the boolit to obturate into a mass of putty and blow gas right by the boolit, or push it so hard it "skids", as 44man likes to say, on meeting the rifling.

Finding the right static fit is step one, balancing the load to achieve good dynamic fit is step two.

[XWrench3]

my s&w 629 was horrible for leading. i checked the barrel, and sure enough, it was terribly restricted right where it went through the frame. i did something just a little different than fire lapping. i pushed a boolit through the bore all the way. took it to the drill press and drilled a hole through the middle of it and inserted a peice of threaded rod and nuts on both ends. (i covered the rest of the rod with electrical tape to keep it from sctatching the muzzle) i then put lapping compound in the barrel with a bent q-tip. sent the boolit back through the bore. i then put a little more compund on the boolit (at this point, you might as well call it a lap) and basicly worked it back and fourth just in the section of the barrel where the constriction was. of course it was slow, tedious (and painfull as i dropped the gun on my big toe and broke it wide open) process. and i had to keep cleaning everything back up and checking my results. i quit with about 1/2 thousandths of restriction still in the barrel, as i got seriously nervous about doing this not really knowing what i was doing. i still get a little leading occaisonally, but the load and type of boolit lube seems to make a huge differnce in this.

[ColColt]

Bret-That makes a lot of sense. All too often I'll look at given powder/boolit combination and usually back off from max about 2 gr or so and work up close to max...sometimes using max (if it's a Ruger) as in the case of the 13.5 gr of 2400. If I see no pressure signs and have easy extraction and the groups are acceptable to me, many times I'll stop whether I'm 2 gr from max or not. I'm not not the 1400+ fps thing although it's nice to know you have a load that will do that accurately and safely.

I stopped by the range on the way home today to pick up the targets from last Friday's trek to the range. The notes I had on four of the targets all indicated lading just ahead of the forcing cone with one load being there and slight traces at the muzzle as well. That one was the only batch I had used 50/50 lead-Linotype. All the others were ww's with tin.

Two loads were with 9 gr of HS-6. One with Lyman's 358429 and the other from a custom mold of same weight boolit. Both leaded some ahead of the forcing cone and the load with the custom mold and BHN 15 leaded some at the muzzle as well with tiny lead streaks down through the rifling.

Another test was 5.5 gr of Universal with the Lee 158 boolit and ww's with tin. It leaded just ahead of the forcing cone.

The last load was 7.5 gr of HS-6 and the Lee boolit with ww's and tin. It also leaded ahead of the forcing cone.

From my notes on each of these targets it appears it's not an alloy problem nor is it a particular boolit problem but rather I need a larger boolit...or the slight possibility I've not measure properly the two boolits I used to slug the bore the other night. I wish I had an entire set of pin gauges. I don't have one quite small enough to slide down the bore and check for a restriction like that. That method seems to me more accurate but first I'm going to work on the boolit and powder. Then, if that fails the only other possibility would be a very slight restriction. The leading just beyond the forcing cone isn't terrible but it's there and shouldn't be.

XWrench3-Fortunately, my M29-3 shoots lead great(knock on wood). After shooting several different loads it looks like I've been using jacketed boolits in the throats as well as the barrel. If it can do that, I need to work on the Ruger.

[Bret4207]

Glad I could help.

The one problem I've found with "slugging" a bore is that not everyone has the same "calibrated elbow and wrist" that can detect a tight or loose spot. In your case Col, considering your notes, I'd still wonder about frame crush. It's hard to slug a revolver like a rifle, but if you could drop and undersize dead soft slug down the barrel and stop it at the area you're getting leading with a dowel you can upset it there with a brass rod or steel rod. Then cut the dowel and drive the slug out the cylinder end. Then take another slug of the same dead soft material and upset it near the muzzle area. You might well find a very measurable difference. That would give you someplace to work from.

[ColColt]

Glad I could help.

The one problem I've found with "slugging" a bore is that not everyone has the same "calibrated elbow and wrist" that can detect a tight or loose spot. In your case Col, considering your notes, I'd still wonder about frame crush. Yep, I'm a little unsure about it myself. I don't feel 100% about it. It's hard to slug a revolver like a rifle, but if you could drop and undersize dead soft slug down the barrel and stop it at the area you're getting leading with a dowel you can upset it there with a brass rod or steel rod. Then cut the dowel and drive the slug out the cylinder end. Then take another slug of the same dead soft material and upset it near the muzzle area. You might well find a very measurable difference. That would give you someplace to work from.

I had a fairly soft boolits(BHN 9.2) and used that as opposed to firing up the pot and casting pure lead as I was anxious to see if I did indeed have the restriction problem. It was a bear to get the slug driven back from the breech end using the method Gear gave possibly to the boolit not being dead soft. I don't know if it mattered that much or not. The boolit was .360" and that could account for the resistence I felt. Perhaps fire lapping wouldn't hurt anyway and after my upcoming tests, that may be the road I have to travel.

[btroj]

I know this is counter what the others have said but I would fire lap it. I can worry over alloy, time/ pressure curves, and the like or I can eliminate what is most likely one of the culprits. If leading still occurs after that I would look at a softer alloy and a larger bullet diameter.
Sometimes the brute force approach just works.

[ColColt]

I like Gear's method of swabbing the barrel/frame junction with 320 Clover and firing one round, clean, and do the same thing about 15 times. I can live with doing that. I have ordered a .359" die that should be here before range time. There's a good possibility that will aid in the problem. Between that tried first and then perhaps the "Gear Method" of fire lapping, I'll have this thing nipped in the bud.

[btroj]

His method has merit. I dis mine the "traditional" way but his certainly will keep the compound out of the throats.
I have a feeling the 359 size will help too. Certainly won't hurt.

[Three44s]

I am a firm believer in lapping if it's really needed but metal ground away can't grow back ..... all you lose by waiting just a bit longer is a little time.

IF you had the book from Beartooth you'd read that the author uses the little egg shapped sinkers for checking dimensions .... being super soft and hollow inside they don't SPRING BACK like a solid bullet and give a more accurate reading.

Those pin gauges will just read the lands and not the grooves. They would be very nice in your cylinders however!

My guess from your last report on leading is that you are in need of a re-run on your forcing cone ..... your mild charge of HS-6 leaded just ahead of your forcing cone .... all arrows point there in my opinion.

Best of luck

Three 44s

[Iron Mike Golf]

..Those pin gauges will just read the lands and not the grooves...

When I set about firelapping my Redhawk, I operated on the understanding that a frame constriction would not only constrict the grooves, but the lands, too. I also operated on the understanding that firelapping would remove barrel steel from both lands and grooves. I firelapped until a pin gauge would pass from muzzle through the forcing cone, which it wouldn't when I started.

Gauging is a lot quicker for checking progress while firelapping at the range than slugging. Should I find the need to firelap another gun, I think I'll try gear's technique.

[geargnasher]

Three44s, while I sure agree that dead-soft is best, and is necessary for accurate actual measurements, any bhn will do for doing comparative measurements, as long as samples from muzzle area and frame area are both significantly over groove dimension to begin with. It's the same thing as calipers vs. micrometers, if you only have a set of calipers, even the cheap digital ones are usually fine for doing comparative measurements like checking for case swage on a pulled boolit. I still think there is thread choke here, but also gas-cutting in the throats from boolits too small for the throats. Fixing the static fit might cure the whole problem.

BTW Bret, EXCELLENT post about pressure-time curves, I can never seem to express ideas as plainly as you can, or in as many different ways.

Gear

[Bret4207]

Thanks Gear, very kind of you to say so.

[Three44s]

Hello Gear,

I understand about your comparitive measurement.

I guess my thinking is that if the OP has a constriction .... it's a small one and small differences .... IE the abilitity to detect it is going to require measuring at a level of "fine art" and the cheap effective and easy to use soft hollow lead sinkers are the best choice along with a fair (nothing fancy needed) micrometer.

Curing a small restriction won't heal the forcing cone assuming his alingement is good.

I also like Bret's pressure time curve post very much. Pressure-Time is what brought me to try HS-6 and has made it one of my most coveted powders.

Best regards

Three 44s

[ColColt]

I could be wrong on this but if indeed there is a restriction it couldn't be more than a few thousands. There must be a fine art to measuring these tiny 1/8th inch wide grooves as I get somewhat of a different reading if I move the boolit just a small fraction. All in all, of the dozen times I've done it with both boolits, I can't get them to vary much...something on the order of maybe .003". I don't know if that's enough to cause the problem I'm experiencing but I'll soon see. I'll use my softest boolits(9.2) with about 5 gr of Universal or maybe just 4 gr of 231 with the 158 gr boolit. Before that, however, Ill try sizing to a larger size, in this case that will be .359".

If restriction is the case, does it matter about the hardness of the boolit I use to fire lap? I have some BHN 9.2 ww's that can be used. I assume those boolits have to be lubed even though I'll be smearing a dab of #320 compound inside the bore with each firing/cleaning.

I thought about this at lunch today. The .358" throat is going to sized them down anyway if I use .359" boolits so, it does no good to use larger bullets. Second and most importantly, chamber pressure will elevate to some degree when bullets are larger than the throats. I'm thinking out loud here but that's what came to mind today. Am I still off base on this? It just made sense.

[357shooter]

I thought about this at lunch today. The .358" throat is going to sized them down anyway if I use .359" boolits so, it does no good to use larger bullets. Second and most importantly, chamber pressure will elevate to some degree when bullets are larger than the throats. I'm thinking out loud here but that's what came to mind today. Am I still off base on this? It just made sense. That's a good point, and I've read several times that sizing large than the throat doesn't matter. For this very reason.

But in my revolvers, sizing larger than the throat size, with soft alloy, is consistently more accurate. So +.003 over groove chambers easily and shoots the best. That's +.002 larger than the throats. That shoots better than +.001 larger than throat size, which is better than throat size.

I know you are working on a leading problem and not accuracy. But I believe this indicates that sizing larger than throats makes a difference. It doesn't make sense, but it does matter. Unless it only occurs in my guns... :lovebooli:lovebooli:lovebooli

[Bret4207]

I could be wrong on this but if indeed there is a restriction it couldn't be more than a few thousands. There must be a fine art to measuring these tiny 1/8th inch wide grooves as I get somewhat of a different reading if I move the boolit just a small fraction. All in all, of the dozen times I've done it with both boolits, I can't get them to vary much...something on the order of maybe .003". I don't know if that's enough to cause the problem I'm experiencing but I'll soon see. I'll use my softest boolits(9.2) with about 5 gr of Universal or maybe just 4 gr of 231 with the 158 gr boolit. Before that, however, Ill try sizing to a larger size, in this case that will be .359".

If restriction is the case, does it matter about the hardness of the boolit I use to fire lap? I have some BHN 9.2 ww's that can be used. I assume those boolits have to be lubed even though I'll be smearing a dab of #320 compound inside the bore with each firing/cleaning.

I thought about this at lunch today. The .358" throat is going to sized them down anyway if I use .359" boolits so, it does no good to use larger bullets. Second and most importantly, chamber pressure will elevate to some degree when bullets are larger than the throats. I'm thinking out loud here but that's what came to mind today. Am I still off base on this? It just made sense.

,003 is night and day in this game!:holysheep I don't know what to tell you other than to get a more accurate measurement. Having a disparity of 3 thou is giving you almost no useful information. Sorry.

[357shooter]

Bret4207 is right on the money. Being off by .003 is too much.

[ColColt]

I didn't add enough zeros...should have said .0003". The marks between each other on the barrel are .001". My findings were closer to the next higher number but less than half from one to the other so, I figured it to be .0003".

[geargnasher]

Whew, glad you posted the correction, ColColt, I was about to jump on the bandwagon! In my experience, anything less than half a thousandth doesn't really need attention, and even a full thousandth restriction can often be dealt with by loading specifically to address the problem. You can "chase tenths" all day as Buckshot puts it, but the important thing is to have an idea of how much the restriction is, and based upon your measurements, there doesn't appear to be much to worry about after all. Size your boolits bigger.

Gear

[Charlie Two Tracks]

I have a GP-100 and I couldn't get an accurate measurement with my mic. What I did was to drive a boolit through the bore and then drop that boolit through the cylinder chambers to make sure that it passed through easily. It did. Then I drove another boolit through the bore five times. The same boolit and marked it so I would start it at the same place on the muzzle. After the fifth time, it pushed through very easily but I could tell that it was a tighter fit at the muzzle than anywhere else. You can tell by the feel if there is any restricton or not. It may not be very scientific but it worked for me. I size all of my boolits at .3585 and use Carnuba Red for lube. I use Unique, AA#9 and H-110 for powders. I use straight AC WW and sometimes a mix that has a BHN of 16. I originally had a problem with leading and found out that my boolit was being swagged down when seating. A Lyman "M" die fixed that.

[ColColt]

Gear-Even though these upcoming boolits will be .001" over throat diameter-that won't increase pressure to any concern?

Charlie-That's a good idea. Scientific or not, if it works, it works. I ordered some Clover #320 and was amazed what it cost for a 1# can...$28 counting shipping!

[geargnasher]

Negative on the concern, ColColt. It might bump chamber pressure a tad, but that will only help matters as far as making the cases seal and getting a good, consistent burn. My understanding is you're not looking to make particularly hot loads, anyway.

Don't get the 1# can, that's Industrial Size! Only automotive machine shops need those, I know of one shop that's done literally tens of thousands of 8-cylinder valve jobs with one can! Get the small, double-ended container with the pry-off friction caps. It will contain two grades of grit paste, and will STILL be a lifetime supply for a young man.

Here's one link I found, note the manufacturer's number 94150 :http://www.repairclinic.com/PartDetail/Clover-Valve-Lapping-Compound/94150/1639276 You can probably find it cheaper somewhere else. It's 120 grit on one end and 280 on the other. I've used the 280 on lots of stuff, and the 120 is handy for fortifying emery cloth during die lapping procedures, it adds a lot of life to the sandpaper.

Gear

PS here's a page that translates the Clover codes to mesh count (squares per inch): http://www.newmantools.com/clover.htm

[ColColt]

I looked several places and the one pound can is all I could find. Well, ****-guess I messed up there. One place I started to order for only $19.95 but when it came down toward the end the shipping charges made it $44! I backed out of that real quick. One thing's for sure, I'll never run out at this point and can lap every mold I've got and probably everyone else's here.

Thanks for the link on that chart. I had seen that before looking for a place to order but forgot where I had ran across it. I'm hoping the 320 will suffice for this job but as mentioned. I'm going to shoot a few with the new size boolit and see where that leads me. While at the range, I may just go ahead and bring a little of the Clover with me and do that as well. May as well be a productive day at the range since they only charge $10 and that's for one hour or half the day.

[357shooter]

I looked several places and the one pound can is all I could find. Well, ****-guess I messed up there. One place I started to order for only $19.95 but when it came down toward the end the shipping charges made it $44! I backed out of that real quick. One thing's for sure, I'll never run out at this point and can lap every mold I've got and probably everyone else's here.

Thanks for the link on that chart. I had seen that before looking for a place to order but forgot where I had ran across it. I'm hoping the 320 will suffice for this job but as mentioned. I'm going to shoot a few with the new size boolit and see where that leads me. While at the range, I may just go ahead and bring a little of the Clover with me and do that as well. May as well be a productive day at the range since they only charge $10 and that's for one hour or half the day.
Sorry to be late with this, but the Wheeler compound has worked well for me. I believe it's less than what you are talking about. It's available on Midway.

[Bret4207]

I didn't add enough zeros...should have said .0003". The marks between each other on the barrel are .001". My findings were closer to the next higher number but less than half from one to the other so, I figured it to be .0003".

Ah! 3 tenths is a whole 'nuther ball game. I would follow Gears advice. I'm still suspicious of a frame restriction.

[ColColt]

Depending on if the roofing guys get out her Friday or not I hope to find out more then. If they make it this Friday it'll be next Friday(my off days) before I can get to the range. I'm most anxious about finding out. My .359" die came today and I suspect the Clover will be here tomorrow. Well, at least I've got two irons in the fire and onward with a solution.

It's hard to fathom that just swabbing the forcing cone area and just into the rifling with #320 on a Q-tip and firing 15 or 20 low velocity rounds would do much for a restriction but, I'm sure going to try it if it merits doing this after seeing the results from the larger boolits.

[geargnasher]

It will do it. Stay under 500 fps, use fast powder like Bullseye, Clays, or Red Dot, and medium-soft boolits like those 9.2 BHN boolits you have cast up. A half-grain of Dacron, fluffed to fill the space between the powder and boolit, no gaps will help immensely here. You will likely have a gritty lube star, so be careful when you wipe the muzzle, it can scratch the surface and ruin the appearance. The Dacron acts like a swab and an extra seal behind the boolit, I've firelapped without the Dacron and won't do it again, it helps in so many ways. You might have to cast some more boolits and size them in your new die, undersized boolits will wear the lands more than the grooves so you want them as large as will chamber safely. .359" should be a minimum.

Gear

[ColColt]

I sized 25 tonight to .359" as they fall from the mold at .361". You sure wouldn't get a Lyman mold to do that. Now...to find some Dacron. I'm wonderinf if the stuffing my dog pulls out of his teddy bears is Dacron? Is it necessary to clean the barrel after each round or just re-swab? I'm a noob at this so you may have to bite your tongue now and then. All the years and decades of shooting and I've never done this so, it's quite a new experience.

[Iron Mike Golf]

Gear, this seems a wonderful technique. I had already lapped my constriction out using Beartooth components and instructions. Tonight I followed that up with your technique to fire-Flitz (minus Dacron filler). Dramatically reduced copper fouling to just a whisper.

I used unsized soft lead bullets over 3.2 gr Bullseye. I did not clean the bore between shots. Just added more Flitz to the forcing cone and 1st quarter inch of the rifling.

Thanks!

[geargnasher]

You're welcome, IMG, glad it worked for you. I don't think I was the first one to do this, but if I heard it anywhere else I can't remember who to give credit for the idea. It's just common sense if you don't want to do anything to the throats.

ColColt, Dacron is the DuPont trade name for polyester fiberfill, the white, springy "wool" that's used to stuff just about everything from quilts to plush toys. Lots of people here comment on recycling their dog's toys for filler when the stuffing starts to come out. Weigh the stuff, you want it fluffy inside the case, not packed down or compressed. "Loft" it by picking it apart, and stuff it in the case with a small allen wrench or flat-bladed screwdriver, let it puff up and pick at it if it's compressed in any spots. Let it come up to just above where the boolit base is and let the boolit just barely push it down when seated. About half a grain should be plenty, maybe less.

I don't bother cleaning the barrel after each shot, do maybe ten with a light touchup of the compound just inside the forcing cone after each shot, then clean and reslug to check your measurements. It might take ten, 20, or 50 shots to get it right, but you obviously don't want to OVERdo it, so check often.

Gear

[ColColt]

That 1# can of Clover 320 came today. There's enough of it to lap every mold in my city I would imagine. The fastest powder I have is probably AA#5 but I do have some old Red Dot(maybe 30 years old) but stuck it out in the garage(attached to the house) years ago as I didn't use it or like it for some reason and put it in a container away from all sources of flames. I opened it tonight and smelled but couldn't detect anything at all-no alcohol or vinegar smell at all. It will burn though, I tried that and it still works.

According to one manual I saw, 5.5 gr of AA#5 will give a bout 700 fps. I could find no data for Red Dot and the 357 but 3.5 gr was indicated for the 38 Special. I suppose either the AA#5 or Red Dot would work for this purpose. I thought for sure the Red Dot would be bad by now but got surprised.

[btroj]

I would use the red dot. Maybe 2.5 grains. You only want the bullet to exit, no more than that.
With 320 grit I would start at 24 shots if a blue gun and 36 for a SS one. Ruger uses some darn tough SS in their guns.
Like someone else said, you can take more off but it is darn tough to put it back.

A 1 pound can will lap everything you own. Twice.

[ColColt]

I would use the red dot. Maybe 2.5 grains. You only want the bullet to exit, no more than that.
With 320 grit I would start at 24 shots if a blue gun and 36 for a SS one. Ruger uses some darn tough SS in their guns.
Like someone else said, you can take more off but it is darn tough to put it back.

A 1 pound can will lap everything you own. Twice.

No doubt. If I had my old 'Cuda again I could hone the cylinders with it.

[ColColt]

I couldn't help but laugh at myself today as I was preparing some rounds to lap out the barrel of my GP100. As I was measuring out 3.5 gr of Red Dot and trying to pull off .5gr of dacron from my dogs teddy bear where he tore out the face and left enough room for me to steal some of the dacron and weighing out that small amount to push into the case, I thought to myself you have to be pretty dedicated to finding out your problem to be doing this. I guess there's a first time for everything.

[geargnasher]

I guess you haven't done much competitive benchrest shooting, have you? [smilie=b:........that sport is purely an exercise in dedication to detail.

Gear

[ColColt]

I guess you haven't done much competitive benchrest shooting, have you? [smilie=b:........that sport is purely an exercise in dedication to detail.

Gear

Nope-The closest I got to that was reloading for the 22-250 trying different powders and bullet combos. I can see how folks could get into it deep, however. I sort of fall in the zone between the standard, run of the mill reloader who wants an accurate load and works it up safely with different powders and bullets and the guys who measure bullet concentricity, weigh primers turn outside necks on bottleneck cases, weigh each bullet and test each finished round for stem to stern concentricity...not my cup of tea. :),

[357shooter]

Hey Colcolt, you doing ok? Wondering when the next installment is coming, this has been a great thread. But we need the final scene, or the next scene at least.

[ColColt]

I've been doing some bible research while awaiting for the weekend to try out my smorgasbord of rounds prepared for this little experiment. I've got about four different loads together with .358 and .359" boolits and 20 with Red Dot for the upcoming possible lapping session.

I've got my lapping compound in a little container so I won't have to take the entire pound can of Clover to the range and Q-Tips. So, I'm ready to roll-just waiting on Friday, my day off. Hopefully, the roofers won't decide to come Friday but wait till the next one. I'm h oping to see just how the .359" boolits will respond and if not, time for the Clover and pip squeak rounds to lap the bore...stay tuned.

[ColColt]

Today I went to the range for the testing procedures outlined during this thread and have mixed feelings about the results. The test involved the loads below and my findings with each.

9 gr of HS-6
170 gr SWC
.359"
BHN 12

This is one of my favorite loads so, I thought I'd try it first. Normally, I had been using the .358" boolit since that's the throat diameter. After 15 shots I checked out the bore and there was a little leading just ahead of the forcing cone, just like before with the .358" boolits. So, I decided to fire lap using the methods Gear recommended and shot 25 using 320 Clover and 3.5 gr of RED Dot behind .5 gr of Dacron. The following load was tried afterwards...

8.5 gr of AA#5
158 gr RF boolit
.358"
BHN 12

I loaded 20 rounds of this one and there was a little leading again forward of the forcing cone for about 5/8". Groups were great being about 1 1/2".

5.5 gr of Universal
158 gr boolit
.358"
Bhn 12

This was identical to the one above.

13.5 gr of 2400
158 gr RF boolit
.358"
BHN 12

This load produced the same results as the one above except there was also a small amount of leading at the muzzle as well. Accuracy was superb with groups being 1 1/4" c-c.

13 gr of 2400
170 gr boolit
.358"
BHN 15

Results as in the one above. It seems the fire lapping did little good. I would like to try the first load again since it was done prior to the fire lapping and using the larger .359" boolit. It may help and may not. I'm a bit puzzled at this point. I used a Q-tip to apply the Clover to the area just ahead of the forcing cone for about an inch after each shot. After six shots, I looked inside with the bore scope and no lead after each string. After cleaning, I loaded another six, applying the compound to the bore after every shot and then cleaning after firing six. I did this for all 25 rounds.

The leading wasn't terrible but was nevertheless there. Most tests were done with 10-20 rounds so, I can imagine it getting worse had I fired 50 or more. I wish I had loaded more with the larger .359" diameter boolit...maybe next time.

[geargnasher]

Why are you puzzled? You firelapped it and then shot undersized boolits through it with every load afterward. Make sure, if you find you need to lap it again, that you get some compound in the end of the forcing cone as well, the restriction will carry through to where the grooves peter out, this area (about the middle of the forcing cone forward) needs attention too. You should be able to see where the boolits have been making contact with the cone, that whole area may be slightly "tight".

Clean the barrel, remeasure the restriction to see what kind of change the lapping made, then go load some .359" boolits of your 12 bhn alloy and the Unique load and try again. I think you'll have the answer at that point.

Gear

[ColColt]

Puzzled because I thought with the fire lapping done, the .358 boolits would be ok instead of having to go to the .359" size-that it was just the restriction causing the leading problem. I did try some of those as well. Some of the Clover was in the forcing cone as it was hard not to get some there while applying the compound just ahead of it. I'll load more in just the .359" size for next time.

[btroj]

Gear is right, no matter how pristine, smooth, and clean a bore is an undersized bullet is likely to lead.
I use .359 in my GP100 and get no leading. I may get a bit after several hundred rounds but it doesn't seem to bother accuracy at all.

[ColColt]

The .358" sized boolits I had been using weren't undersized, per se as they matched the diameter of the throats of the cylinder. Apparently, in some guns that doesn't work, as in this case, and a slightly larger one is in order. Now, my M29 can use exactly throat diameter boolits and not experience any leading at all, matching .432" boolits with .432" throats. The GP100, on the other hand, seems a bit more demanding.

[geargnasher]

The .358" sized boolits I had been using weren't undersized, per se as they matched the diameter of the throats of the cylinder. Apparently, in some guns that doesn't work, as in this case, and a slightly larger one is in order. Now, my M29 can use exactly throat diameter boolits and not experience any leading at all, matching .432" boolits with .432" throats. The GP100, on the other hand, seems a bit more demanding.

Yes, but what's your M29's groove dimension? I'll bet a shiny nickel that it's .429" on the money if you have the tools to measure 5-groove bores. You aren't comparing apples-to-apples, here. For one thing, your GP100 has a groove dimension, after being slugged all the way through, of .357" if I remember correctly, and the cylinder throat diameter (assuming all the same, a BIG assumption with gang-bored and gang-reamed ruger cylinders which often are a mix of old and new reamers) was <.3585" but >.3580", so there's about a thousandth difference here, where your Smith swages the boolit about .003".

You're right, having a boolit you can assume is .358" hitting the forcing cone of a .357" barrel ought to seal and not lead, but your gun has been telling us all otherwise all along. I think part of the problem is in the cylinder. Based on the results from before, and my own experience with an ornery GP100, this one is going to take some work to be able to shoot .358" boolits. I was suspecting a gas seal break in the cylinder throats themselves, that's why I suggested using a boolit that was BIGGER THAN THE THROATS and seating them so they would chamber against the cylinder forcing cone, thus being a force-fit through the cylinder and never getting a chance to leak before entering the forcing cone. If the lube gets blown off and one side of the boolit gas-cut before the boolit engraves, it will lead no matter what you do. Note how the loads with 2400 leaded the whole barrel with your most recent test, that tells me the boolits were gas-cut so badly by the time they made it into the barrel that there was no chance of achieving obturation. Either that, or there still is some thread choke and it's worse than we figured.

I currently am in posession of my buddy's GP, I'm going to go dig it out of the safe and double-check some measurements and give you some load data that I KNOW works. Stay tuned....

Gear

[btroj]

I have only used .359 for bullets I cast. I did shoot some commercial cast though. They were marked .357 but were actually .356. I could have mined the barrel it had so much lead in it.
I am with Gear on this- use a bigger bullet so it seals the throats. .359 could make all the difference in the world.
Try this- how easily can you push a .358 bullet thru the throats? Might be eye opening.

[geargnasher]

Ok, I'm back. I forgot it was a stinkin' five-groove, so I had to slug it again and re-measure. Turns out the groove circle is .357" also, but the actual mean radius is .178", which means that a boolit sized .356" would just barely fill the hole. I reamed the throats to .358" and honed to about .3582-3", and my best load for the pistol is the Lyman 358665 "Cowboy Action" 158-grain BB RFN. I had to lap and Beagle it to make it cast .3590"x.3595" boolits. Alloy is 15 BHN ACCOWW+2% added pure tin, sized .359". The load is 5.6 grains Hodgdon Universal lit with CCI-500 SP primers, and the lube is Felix World Famous lube. Medium roll crimp in the groove is plenty. This gives 1.5 inch groups at 15 yards from the bags, not stellar, but far better than I got with HS6, and better still than the minute-of-milk-jug 10-yard accuracy that it displayed when I first took it in. Reaming/polishing the throats, lapping the thread choke, polishing the forcing cone with a lead lap on the end of a cleaning rod, and shooting a boolit that was bigger than the cylinder all added up to success for me, it should in yours too.

Gear

[357shooter]

My 357 revolvers have always shot best with bullets over throat size, which is over groove size. .002 over-throat shoots best in 6 groove 6-6.5 inch barrels, for me.

Don't have a 5 groove to wring out, that could be different.

[ColColt]

Yes, but what's your M29's groove dimension? I'll bet a shiny nickel that it's .429" on the money if you have the tools to measure 5-groove bores.

Gear-You're absolutely right-it is .429" so yes, there's a .003" difference between groove and throat diameter. My GP has a groove diameter of .357" but they closely approximated that with the .358" throats which I thought was ideal from all I've read but as indicated every gun obviously is a bit different and don't follow the rules according to Hoyle and this is a prime example. Suffering under the delusion that if I sized to throat diameter all would be peachy but experience has taught otherwise.

When I was making up some rounds to take to the range, I thought I had made more .359" that what I did. I will rectify that next time. The boolits I used for the lapping were the lee 158 gr RF backed by the Red Dot and sized to .359". I have no idea what the velocity was but after 25 rounds there was zero leading and those were soft BHN 9.2 boolits. That load you used in your friends GP closely approximates the one I used yesterday with 5.5 gr of Universal with the exception of the dimension of the boolits. That was a lot of work on your friends GP to say the least. I trust he was most appreciative of your efforts.

The most accurate load I shot was a new one-8.5 gr of AA#5. That may take the place of others I've used...IF I can do it again. It's amazing how that cheap little Lee mold boolits (358-158-RF) shot better than the ones produced from a custom mold. These guns-simply individual regardless.



btroj-I can shove a .358" boolit though the throats fairly well with a bit of spinach under my belt. I can't shove the .359", however. Maybe my thumb is too weak.

[geargnasher]

ColColt, this is a perfect example of how each gun is a law unto itself. It's impossible to establish "rules of thumb" that hold water, or even valid guidelines because there are always exceptions. The important thing is to try what "should" work (like you did several times here), and listen to what the gun and target tell you, assume only as much as you have to to fill in the blanks on your first few load workups.

Gear

[Doby45]

I am with Gear on this brother, try the .359 boolits. I might even look into getting a .359 reamer for the throats.

[ColColt]

I checked into the reamers and Brownell's has the Manson(not Charles) for $50 for the 38/357. It seems that reamer only goes up to .358". Never tried that before but have read about folks doing it.

BTW-What is a lead lap?

[Iron Mike Golf]

ColColt, I agree with gear. Your chamber throats are likely not perfectly round and there are likely spots where you can see daylight between a .358 bullet and the wall of the throat. You might give that a try. If you see daylight, then gas can blow by before the bullet seals the bore, carrying some lead with it (all the way to the muzzle).

In my Redhawk, I did not stop the leading until I firelapped out the frame constriction and honed my .431 sizing die to .433. The throats gauged .432, but I could see arcs of daylight with a .432 bullet and .432 pin gauge.

My setup is now .433 bullet, .432 throat, .430 groove dia.

[357shooter]

.360's shoot great in my guns, that's with a .357 groove and .358 throats. .358 and .359 don't shoot as well.

Try .360 first. If the throats are still big, why make them bigger, try a bigger bullet first. Just because a .359 didn't work it's worth a try with .360. Or if unsized will chamber, try that.

[ColColt]

ColColt, I agree with gear. Your chamber throats are likely not perfectly round and there are likely spots where you can see daylight between a .358 bullet and the wall of the throat. You might give that a try. If you see daylight, then gas can blow by before the bullet seals the bore, carrying some lead with it (all the way to the muzzle).



In all likelihood, this is very probable with mine as well. Not that it is, but still probable. I get good accuracy with some loads giving 1" at 10-15 yards...it's just the leading problem I have. You would think if the bullet's not obturating properly, the accuracy wouldn't be that good. Next range trip I'll have .359" boolits in both styles of boolits I shoot and see what the outcome may be. I live in hopes this will cure the problem. Perhaps in some instances my alloy isn't hard enough for the pressures/velocity the loads have. That could be a factor as well as the size of the boolit. However, and this is another pistol and another caliber but, it doesn't seem to matter what I shoot in my M29, it doesn't lead with .429" groove diameter and .432" boolits. That tells me something right there. So, in the immortal words of Buzz Lightyear..."To infinity, and beyond!".


Try .360 first. If the throats are still big, why make them bigger, try a bigger bullet first. Just because a .359 didn't work it's worth a try with .360. Or if unsized will chamber, try that.

I only have a .358 and .359" size die and really haven't given the .359" boolits much of a chance yet as I didn't do a full test with them the other day. I'm going to give it another go next range session. The throats are .358" so the .359" boolit may very well do the trick. More testing needed.

[geargnasher]

I checked into the reamers and Brownell's has the Manson(not Charles) for $50 for the 38/357. It seems that reamer only goes up to .358". Never tried that before but have read about folks doing it.

BTW-What is a lead lap?

ColColt, the suggestion that your cylinder throats may be out of round is more than likely true, one of the many reasons to go bigger with your boolits. Like was explained, going bigger and letting the gun size the boolits the way it likes is a good way to build in "fudge factor" that can compensate for mechanical and dimensional imperfections which would otherwise allow gas leaks (loss of obturation). The GP I fixed still has one throat that has a triangular area which builds lead and hard powder fouling due to being oval (not elliptical, a true oval or egg-shape) at the cylinder mouth, but round at the end of the cylinder's throat or leade. I don't clean that throat too well, I just leave the fouling in there and let it act as a filler.

I wouldn't get too carried away with reaming the throats unless it proves to be an absolute necessity, and only then by doing a chamber test where you fire a large number (say 20) rounds through each chamber to check that chamber's grouping, point of impact, and tendency to foul or lead. If you get one bad apple, mark it and quit using it if it bothers you, or maybe you can figure out a way to correct it just by reaming or honing if it's undersized.

As for reaming, forget the expensive throating reamers, just order a chucking reamer in the size you need (probably .3585") from one of the tooling supply houses (If it comes to that PM me or Bret4207, we know which one to use) and bush it very carefully with masking tape to fit the chamber so it will pilot and not wobble while it's cutting. Then you can hone a bit with a split dowel and some oiled 400-grit paper. But like I said, this is really a last resort to fix a problem that can't be fixed any other way, and I don't think it will come to that with this pistol. Maybe more firelapping, in fact probably more, but don't mess with the cylinder yet.

As for the lead lap, I made a lap from a .45/70 boolit by drilling and tapping a hole in the nose to fit my cleaning rod, then used my drill press and a file to shape it into a skinny cone that matched the angle of the forcing cone as the factory cut it, then I embedded the lap with 280 Clover by rolling it on a steel bar, inserted the rod through the barrel, screwed the lap onto the rod, and spun the rod with a cordless drill, pulling it into the forcing cone and out like a sewing machine bobbin. After a few seconds I added more compound and did it again, just like lapping valves on a 4-stroke engine. It doesn't take much to really polish it up and get all the awful factory gouges out of the cone, and that keeps it from scraping/tearing lead from the boolit as it engraves.

Gear

[Bret4207]

In all likelihood, this is very probable with mine as well. Not that it is, but still probable. I get good accuracy with some loads giving 1" at 10-15 yards...it's just the leading problem I have. You would think if the bullet's not obturating properly, the accuracy wouldn't be that good. Next range trip I'll have .359" boolits in both styles of boolits I shoot and see what the outcome may be. I live in hopes this will cure the problem. Perhaps in some instances my alloy isn't hard enough for the pressures/velocity the loads have. That could be a factor as well as the size of the boolit. However, and this is another pistol and another caliber but, it doesn't seem to matter what I shoot in my M29, it doesn't lead with .429" groove diameter and .432" boolits. That tells me something right there. So, in the immortal words of Buzz Lightyear..."To infinity, and beyond!".



I only have a .358 and .359" size die and really haven't given the .359" boolits much of a chance yet as I didn't do a full test with them the other day. I'm going to give it another go next range session. The throats are .358" so the .359" boolit may very well do the trick. More testing needed.

Okay, I think I see where part of the issue is above and it ties in with something else you said, "Puzzled because I thought with the fire lapping done, the .358 boolits would be ok instead of having to go to the .359" size-that it was just the restriction causing the leading problem." First off, I'm not a fan of the obturating theory as an aid to accuracy and cure for leading. Yes, it can work, but it can also fail. Depending on obturation is depending on slamming that meticulously crafted, carefully loaded boolit with so much pressure that it becomes a mass of putty and is, hopefully, forced outward into the throat while it's still expanding and will hopefully seal the bore/grooves, but hopefully we won;t slam it with so much pressure ithe gas just blows right by the boolit. We also hope that each shot will be the same pressure and that each boolit will react the same. That's an awful, awful lot of hoping we're relying on there.

Better in my opinion to get the boolit fit to the gun to start with and not depending hope, chance and luck to cure our problems. When you fire lapped, even though you didn't hit the throats, you still hit all of the barrel beyond where the compound started. You altered you dimensions. You might have removed your constriction,if there was one to start with, but you still have to fill the grooves. To may way of thinking if I had done what you did I'd be thinking, "Okay, now we're at a point where "hopefully" my boolit isn't getting swaged down by the restriction. Now I should be able to use a throat filling, groove filling boolit." It's the very rare gun/boolit/load combo that wants a smaller diameter boolit. One of the older sayings around here is, "If it'll chamber, shoot it and see". IOW, using as large a diameter boolit as possible often gives good results. I have had excellent results using unsized boolits in many guns. Whether this is due to sizer damage being avoided or the larger diameter I can't say, but it often gives very good results. So first thing is to see what our mould drops. If it's larger than .359 then at least consider the option of using a larger yet boolit than your .359's. Give the .359's a workout too. Change only one thing at a time. That pre and post firelapping test really showed nothing since you changed ammo.

[ColColt]

This revolver shoots very good and I know if I had it in a Ranson rest, it would probably give 1/2"-1" groups but I can't do that well without a rest of some sort. I'm not disappointed in the groups-just the leading. I will beat this thing one wa or the other. I wouldn't even mind a small amount of leading but I'd be filled with euphoria if it left a bore like my M29-which is zero lead. I may have to get a ticket to Fantasy Island for jthat pipe dream, however.

I wold like to see the forcing cone and throats a little smoother but that's secondary to the current problem. Again, I don't want to overemphasize the fact that it's leading because it's not really all that bad. Certainly nothing half a dozen passes with a brush and Chore Boy doesn't cure.

Bret-As for the obturation, I've been told my boolits weren't hard enough for the chamber pressures I'm getting with the loads I use and that I should use anywhere from a BHN 15-24 depending on the load. That just sounds way too hard for me but he does know a lot more than myself. Matter of fact, most anyone knows more than I about this. My M29 doesn't care what the bullet hardness is as I've used ww's to Lyman #2 and no leading.

I have two molds and one drops a .360" boolit and the other .361"-both with ww's and a dash of tin. The other mold you can forget(Lyman) as it's .357-.358". For now, I'm going to load several loads with AA#5 and maybe Universal and HS-6 with all .359" boolits and see how it goes. These give the best accuracy with 158 and 170 gr boolits in my GP

[Iron Mike Golf]

ColColt, I have come to the opinion that alloy hardness and toughness should be chosen for resisting in-bore and in-chamber deformation (called "slump", "bumping up", or "upset") and for terminal ballistic effects desired (not really a factor for paper punching).

This runs counter to recommendations to keep the alloy malleable enough to obturate as a result of the pressure spike. The thing that concerns about "bumping up" to obturate is that is it not only the base that deforms. The whole bullet does. Does the nose of a SWC deform with excellent symmetry around the bore axis? I don't know, but I wonder. This might not be an issue with a wadcutter design. I'd rather ensure obturation with baseline dimensions.

I can shoot 452460s from my Mk IV Series 80 that have a hardness of 24 BHN using 5.0 gr Bullseye with no leading. I seriously doubt that the pressure spike is making that bullet obturate.

[geargnasher]

IMG and Bret, you both make good points about keeping the peak pressure below the yield strength of the boolit, this almost always produces the best accuracy for the reasons mentioned (no base deformation or nose slump, etc.), and I agree fully that's the best approach. I only mentioned trying to bump the boolit later in the timeline because sometimes it is possible to fudge a bit, using a slow powder at higher pressure loadings to get the boolit base to punch up a bit after it's already safely engraved in the bore. Specifically, I was suggesting trying to tweak the load around a possible barrel-frame restriction, and I've had success doing just this with .357 Magnums before, the trick is to use enough powder, JUST soft enough alloy, and work things so that the peak pressure happens just about the time the boolit base gets past the forcing cone, which will either punch the base to seal after the restriction, or blow the obturation completely making gas-cutting and leading even worse. I've seen it go both ways. Yes, it's a half-arsed, backward, longshot way of working around a dimensional problem, but I thought I'd throw it out there as an alternative to lapping.

Gear

[Bret4207]

ColColt, I have come to the opinion that alloy hardness and toughness should be chosen for resisting in-bore and in-chamber deformation (called "slump", "bumping up", or "upset") and for terminal ballistic effects desired (not really a factor for paper punching).

This runs counter to recommendations to keep the alloy malleable enough to obturate as a result of the pressure spike. The thing that concerns about "bumping up" to obturate is that is it not only the base that deforms. The whole bullet does. Does the nose of a SWC deform with excellent symmetry around the bore axis? I don't know, but I wonder. This might not be an issue with a wadcutter design. I'd rather ensure obturation with baseline dimensions.

I can shoot 452460s from my Mk IV Series 80 that have a hardness of 24 BHN using 5.0 gr Bullseye with no leading. I seriously doubt that the pressure spike is making that bullet obturate.


I have to add to that- The problem is the whole boolit MIGHT or MIGHT NOT bump up! We don't know just what happens or doesn't happen between shots. One shot might bump the whole boolit, the next might not. The more pressure, the more bump, the more chance for bad things to happen.

I agree with your overall assessment.

[Bret4207]

This revolver shoots very good and I know if I had it in a Ranson rest, it would probably give 1/2"-1" groups but I can't do that well without a rest of some sort. I'm not disappointed in the groups-just the leading. I will beat this thing one wa or the other. I wouldn't even mind a small amount of leading but I'd be filled with euphoria if it left a bore like my M29-which is zero lead. I may have to get a ticket to Fantasy Island for jthat pipe dream, however.

I wold like to see the forcing cone and throats a little smoother but that's secondary to the current problem. Again, I don't want to overemphasize the fact that it's leading because it's not really all that bad. Certainly nothing half a dozen passes with a brush and Chore Boy doesn't cure.

Bret-As for the obturation, I've been told my boolits weren't hard enough for the chamber pressures I'm getting with the loads I use and that I should use anywhere from a BHN 15-24 depending on the load. That just sounds way too hard for me but he does know a lot more than myself. Matter of fact, most anyone knows more than I about this. My M29 doesn't care what the bullet hardness is as I've used ww's to Lyman #2 and no leading.

I have two molds and one drops a .360" boolit and the other .361"-both with ww's and a dash of tin. The other mold you can forget(Lyman) as it's .357-.358". For now, I'm going to load several loads with AA#5 and maybe Universal and HS-6 with all .359" boolits and see how it goes. These give the best accuracy with 158 and 170 gr boolits in my GP

Who told you? Yeah, harder CAN work, if it fits in the first place. SOME harder alloys resist deformation more than others. Some seem to react an awful lot like their AC counterparts on ignition. I think the alloys makes a diff. It's take experimentation to figure this out, but fit always comes first.

[ColColt]

At his point I'm confused about all I've read from different places. I've read where obturation is the key to performance and a non-leading bore while staying within safe pressures and optimizing the load-proper sized boolit, medium burning powder and the right BHN value. What I've real long before this problem came up was all about picking the right powder/boolit combination and the proper hardness of the boolit and y ou would have accuracy, safety, and a bore that's not laden with lead. I don't think a BHN 9-10 boolit would fare well with velocities in the magnum ranage but on the other hand, I don't believe a BHN 22 boolit would do very well with target velocities either.

I keep about as many boolits that's been cast with 50/50 lead to Linotype as I do ww's and tin. Those are my primary alloys. I've tried sizing to .358" and that apparently didn't work as intended with those alloys and the loads aforementioned. So, Now I'm going to see if the larger diameter boolit will solve this equation. I tried my hand at fire lapping the easy way and that didn't see to matter although perhaps I needed to fire twice the amount of rounds I did(25)...I don't know. It's all beginning to be a little frustrating.

[462]

"I keep about as many boolits that's been cast with 50/50 lead to Linotype as I do ww's and tin."

Sir,
It could be you need a softer boolit.
Before you go further with gun modifications, try a 50/50 wheel weight/lead alloy. Nix the tin and let the boolits cool on their own.

Just saying.

[geargnasher]

At his point I'm confused about all I've read from different places. I've read where obturation is the key to performance and a non-leading bore while staying within safe pressures and optimizing the load-proper sized boolit, medium burning powder and the right BHN value. What I've real long before this problem came up was all about picking the right powder/boolit combination and the proper hardness of the boolit and y ou would have accuracy, safety, and a bore that's not laden with lead. I don't think a BHN 9-10 boolit would fare well with velocities in the magnum ranage but on the other hand, I don't believe a BHN 22 boolit would do very well with target velocities either.

I keep about as many boolits that's been cast with 50/50 lead to Linotype as I do ww's and tin. Those are my primary alloys. I've tried sizing to .358" and that apparently didn't work as intended with those alloys and the loads aforementioned. So, Now I'm going to see if the larger diameter boolit will solve this equation. I tried my hand at fire lapping the easy way and that didn't see to matter although perhaps I needed to fire twice the amount of rounds I did(25)...I don't know. It's all beginning to be a little frustrating.

Look, it's really simple. The boolit needs to be able to get from the cartridge case to the muzzle crown with as little gas leakage as possible, period.

How you achieve and maintain the seal ("obturate" is a medical term we borrow to mean "blockage" or "seal" of the boolit/barrel interface, obturation of the bore is achieved if we create a leak-free dynamic seal) is what's giving you fits, and most of us just love to complicate the heck out of it. I think Chargar is probably lurking on this thread so disgusted that he won't even post!

Possibilities for leakage are, but not limited to:

1. Boolit being too small to begin with.
2. Boolit being swaged by the case when seated.
3. Boolit too small for cylinder throat due to #1 or #2.
4. Excessive cylinder gap, poor cylinder/bore alignment (shaving), or forcing cone cut too deep.
5. Rough and/or restricted forcing cone, restriction being relative to the barrel forward of that point.
6. Barrel restriction at frame, making boolit too small for the rest of it's trip down the pipe.
7. Other restriction in barrel, from roll-lettering, ejector rod housing attachment, front sight fixture, etc, leading will occur at and after such points.
8. Any point after the forcing cone that is LARGER than the cylinder throats.
9. Boolit skid. This is a biggie with revolvers. Boolit is too soft for how fast it's being accelerated with a given powder. The boolit travels a relatively long distance before encountering rifling compared to other gun designs, and as it enters the rifling and the rifling has to impart a spin suddenly to a boolit already going nearly it's full speed, the static rotational inertia of the boolit resists and the rifling partially "strips" the engrave. If the strip extends to the base band, it will open gas leaks at the trailing edge of each land, causing lube blowout and severe gas-cutting/leading, usually following the lands the full length of the barrel.

Think it over, consider all you've been told, maybe do some more measuring, and see if it doesn't start to make more sense.

If I've confused you even more, I sincerely apologize, like everyone else, I'm only trying to help you get this sorted out.

Gear

[runfiverun]

i'd just shoot the thing.
try some hot jaxketed loads for a bit.
then shoot it some more.
if the leading don't go down the bbl or make 10" groups why sweat it.
follow up with some gas checked rounds once in a while or some store bought stuff.
lap it a bit with some boolits rolled in the valve compound shot easy down the bbl.
heck you might even improve the trigger with all the shooting.

[Bret4207]

At his point I'm confused about all I've read from different places. I've read where obturation is the key to performance and a non-leading bore while staying within safe pressures and optimizing the load-proper sized boolit, medium burning powder and the right BHN value. What I've real long before this problem came up was all about picking the right powder/boolit combination and the proper hardness of the boolit and y ou would have accuracy, safety, and a bore that's not laden with lead. I don't think a BHN 9-10 boolit would fare well with velocities in the magnum ranage but on the other hand, I don't believe a BHN 22 boolit would do very well with target velocities either.

I keep about as many boolits that's been cast with 50/50 lead to Linotype as I do ww's and tin. Those are my primary alloys. I've tried sizing to .358" and that apparently didn't work as intended with those alloys and the loads aforementioned. So, Now I'm going to see if the larger diameter boolit will solve this equation. I tried my hand at fire lapping the easy way and that didn't see to matter although perhaps I needed to fire twice the amount of rounds I did(25)...I don't know. It's all beginning to be a little frustrating.

Look, I don't have your gun here to play with, wouldn't have time anyways, but there's a set of problems or truths or issues you have to wrap your mind around first off- each gun is different, some by a lot, some by a little. Everyones alloys are a little different unless you're using store bought. Each mould, sizer and die is a little different, each batch of gun powder differs a little, so do runs of cases and primers. Each persons culling of their boolits differs. All these little things add up, some cancel each other out and some multiply. So IMO you need to understand that there is no ONE answer that always works to solve every cast issue. This guy you PM'd me about is a Bhn guy, to him it's all about Bhn. He's got nice numbers that say as pressure rises you need a higher Bhn number, makes sense, he can give nice numbers that seem like they should work. It's entirely possible that it does- in his guns! I can guarantee you that I can show it doesn't work in all guns, especially since he says size everything to .358. That might work fine in his guns, it won't in some of mine no matter how hard he makes them. I spent good dollars on a 500 count box of super hardcast boolits that had SILVER in them!!! I mean, come on! They have SILVER in them!!! They HAVE TO BE THE ANSWER! Right? Nope, shot like krap no matter what load I tried. They were .358, 2 of my Smiths like .359-.360, one like .359 and my Colt likes .358 if not .357, got to shoot more to figure that out for sure yet. And to add more to the mix my 35 Whelen likes .360+ and my pre-MG Marlin 35 Rem seems to like anything and everything!

So, what to do? in your case you still need to determine if you have a possible constriction in the gun. Then you need to start with static fit, I start with the largest boolit that will chamber easily. If that means unsized, so be it. Then I start low and slow and work up. If I get good, round groups that are about the same size as jacketed at 850 fps I keep working up. (You can take a 30Bhn boolit and get great groups at 850 fps, Bhn is no bar, or should be no bar, to shooting slow. If they won't shoot slow, then you have a fit issue if a 12 Bhn of the from the same mould does!) If groups start to open when you hit 1100fps, for instance, and/or you start to get leading, then it's time to go to work. You change one thing at a time and record it all. You change any of the following things and more-

Seating depth, crimp, size, lube, primer, powder, powder charge, case brand, filler/no filler, add a GC if shooting bare bottomed, alloy, HT or not...probably a few I forget.

Me, I start simple. I check to make sure the boolit isn't getting "squished" when seating. Then I play with the crimp. If that makes no difference or makes it worse I might either go to a slower powder, play with seating depth or add some powder to see if it get's progressively worse. If worse or no change I might size differently- go up or down and see if there's an effect that's good. I look for changes that indicate progress. IOW- if I crimp a little harder and the leading disappears but the groups don't change (get larger) then I keep the crimp but look at maybe using a larger boolit since that MIGHT tell me that the powder needs a bit more neck tension to ignite right and that as the pressure rises the boolit might need a better grip on the rifling. I can change alloy too, but then I'll have to still crimp harder which allows for me distorting the boolit. And I keep playing from there.

Some guys here probably have a written progression they use. I don't because I haven't figured one out yet. But that's the way the game gets played in my world. Doesn't mean that's the only way, but it's one way.

You also may have to re-consider cast at all if this is too frustrating. Cast isn't for everyone and some guns, maybe 10%, are just not cast friendly.

[Iron Mike Golf]

... I don't believe a BHN 22 boolit would do very well with target velocities either....

I cast water cooled 452460s and load them over 5.0 gr Bullseye for .45 ACP. 24 BHN after 1 week with my alloy. They shoot beautfully in my Mk IV Series 80 and Donaldjr1969's P90. No leading in either because sized to .452 they fit well in both guns.

...I tried my hand at fire lapping the easy way and that didn't see to matter although perhaps I needed to fire twice the amount of rounds I did(25)...I don't know. It's all beginning to be a little frustrating....

Is your gun stainless? If so, 25 rds is likely 25% of the way there, as far as firelapping goes. I recommend using a pin gauge in the bore to quantitatively measure progress. Any constriction will compress the lands as well as the grooves. When I firelapped my RH, I gauged the barrel after every cylinder of lapping loads. It took just over 100 rounds using 320 grit to remove the constrictions (as measured by pin gauging). Before and after groove diameter measured .430 by slugging. If I ever firelap a stainless Ruger again, I will start with 220 grit.



(need 5 more charcters to post?)

[Bret4207]

"(need 5 more charcters to post?)" Yup, didn't ya read the Newfie password joke- Minnie, Mickey, Donald, Pluto, Scooby......:mrgreen:

[ColColt]

Think it over, consider all you've been told, maybe do some more measuring, and see if it doesn't start to make more sense.

If I've confused you even more, I sincerely apologize, like everyone else, I'm only trying to help you get this sorted out.

Gear

I'm not confused, Gear-no apologies necessary. I've just read too much. Before posting this thread I had read from the LASC website a month ago and many articles by Glen Fryxwell and from the Ruger forum and everything started running together. You and others have done a superb job instructing me and the time and efforts you guys have given have been overwhelming and I say again, most appreciative and that's an understatement.

Not being a seasoned vet with cast boolits, it's easy to get your wires crossed. Up until I joined the forum I had happily shot cast boolits not taking into consideration fit between throat, boolit and bore that much. I bought a 45 Ruger years ago and a Lyman mold, 429421, cast boolits from 50/50 Linotype and lead size to .454" and think I had a great combination. I thought leading was just the byproduct of shooting lead and just boght a Lewis Lead Remover and went on with it. I didn't know any thing else then. Being here has been a totaly rebirth for me.

I think at this point the best advice is to just try the larger .359" boolits and see what that produces. If I see an improvement in the leading fiasco, perhaps even try a .360" boolit which means unsized as my molds drop boolits that size. Maybe I've been doing too many different things and have gotten all balled up with that so, I'm going to take it one step at a time now.

Bret-In seating the boolit, I flare just enough to cover half of the base band and easy seating so, there should be no squishing of the boolit in that step. One thing I've noticed in inspecting the bore/forcing cone area with a bore light is that the small transition between the forcing cone and just when the rifling begins, it seems the rifling has several "steps" before a continuous rifling...sort of choppy for lack of a better word. In other words, it's like whatever method used to cut the rifling didn't grab and cut smooth enough and left these 3-4 little steps...I dont know but, that's the way it looks. I'd post a pic but photographing that area is next to impossible.

[462]

:...In seating the boolit, I flare just enough to cover half of the base band and easy seating so, there should be no squishing of the boolit in that step."

Have you ever pulled a boolit and measured it?

Regardless of what you do to the case mouth, so that it will accept a fat boolit, the seater die can swage it down to a jacketed bullet dimension. I had many Lee dies that were doing that.

[ColColt]

[I]

Have you ever pulled a boolit and measured it?

Regardless of what you do to the case mouth, so that it will accept a fat boolit, the seater die can swage it down to a jacketed bullet dimension. I had many Lee dies that were doing that.

Never measured one. They've always seated easily without any felt undue pressure but, it sounds like it's worth trying. If it does compress it, there's not much you can do if you're trying to get a .359-.360" diameter boolit in a case.

[462]

Well...you could:
1. Get a fatter sizing stem.
2. Get a different brand of seating die.

I had many problems with Lee dies swaging down boolits. I've never had a problem with Lyman dies.

By the way, are you seating and crimping in one operation, or two? If one, try two. Sometimes doing both at once will shave some lead from the boolit's base.

[btroj]

The key is that sometimes what seems so minor, so inconsequential can be a huge part of the problem.
I think that trying .359 bullets is a great starting point.

[geargnasher]

Never measured one. They've always seated easily without any felt undue pressure but, it sounds like it's worth trying. If it does compress it, there's not much you can do if you're trying to get a .359-.360" diameter boolit in a case.

:groner: Ok, after all of this, I have to ask you to do one thing. Grab a shovel. Grasp firmly with both hands. Apply briskly to your forehead. Repeat as necessary!!! Say "DOH!!" in a Homer Simpson voice! :kidding: After you regain your senses, go back to post #101 and reread my list of things that cause leading in revolvers, particularly #2, the part about case swage. [smilie=b:

NEVER assume anything, measure it. All of the explanation Bret gave about static fit, dynamic fit, pressure, etc. is aimed at keeping the boolit sealed from launch to exit. Measuring a pulled boolit is one of the very first things I check with ANY gun shooting cast, for one thing it is a measure of case tension. You can't tell us you're shooting .358" boolits just because they were .358" when you stuffed them in the cases and crimped them. You also can't assume that your boolits fit the throat just because a sized one goes through with heavy thumb pressure. You can have an idea of whether or not they fit the throat if you load a dummy, crimp as you normally would, pull the boolit with an inertial puller (with a cotton ball in the nose end of the hammer so it doesn't damage the boolit when it comes out), then try THAT boolit through the throats. The cases could be swaging the boolits to .3575" or more, which could be the whole source of your issues. Then it could be your crimp, if the cases are hard and the boolits soft, the crimp could be raking .001" or more off of your driving bands. Load and pull a boolit without crimping and see if you can tell the difference if you suspect overcrimping. If the boolits are coming out of the cases the same size you put them in, then you're ok there, just go up a thousandth or more on the boolit size and try again. You aren't going to blow up that Ruger with a boolit that's a couple thousandths bigger than the cylinder throats.

Gear

[Bret4207]

Most of my screw ups and mistakes come from making assumptions. For instance, I assumed that a sizer marked .311 would leave me with a .311 boolit, not the .3093 or 4 that it did. I assumed harder meant better, that it was a cure for everything from leading and inaccuracy to male pattern baldness and my multiple chins. I even assumed that my wife really meant it when she said, "Fine." Woe be unto thee who assumeth anything! And ya know what the really frustrating part is? A lot of our search for fact involves us butting our heads up against our assumptions. So after ya get done smacking yourself with the shovel (you don't have to do it very hard actually!) pull a few and see what they measure. At least get it out of the way.

Your gun only has 75-100 jacketed through it, so I'd consider running a couple hundred more jacketed and see what your grouping does. Often time a gun settles down after a few hundred rounds. Works with cast or paper patched too, but it takes a lot longer.

[ColColt]

This thread has taken up way to much "cyber space" and more than enough of everyone's time so, I'm just going to start with the .359" size, check all that's been aforementioned and go from there. If there's still a problem ever how small or large, I'll look at all the suggestions one by one. I have plug gauges but none small enough to drop in the bore to check for constrictions so, that may be another viable alternative as it would be more accurate(for me) to check that way. A five groove barrel is not the easiest to measure groove to groove when slugged.

This is getting way too complicated to be fun and shooting/casting should be fun and enlightening. Obviously, it's some quirk about this particular gun as I haven't had a problem quite like this before...not to this degree at any rate. I'll pour back over the suggestions if all else fails after trying the new powder that did well last time (AA#5) and with the larger boolit and go from there. Perhaps I'm expecting to much o f this particular gun. the groups I can't complain about. I was wanting no lead at all but that may be just a dream with this one. As I've mentioned earlier, the leading isn't great and can be brushed out fairly easy. I just wanted no leading at all and that may not be possible. By the small amount of leading being primarily just ahead of the forcing cone, I still suspect either a rough cut there or there's still some small restriction or both. For brevity's sake I may just get an entire set of plug gauges and go that route to check. It doesn't hurt to have them available.

[geargnasher]

Plug gauges can and will get you into trouble because, as was mentioned earlier, they will only measure the minor diameter of the hole. No accounting for elliptical or oval holes. Lead slugs are the best way. If you have a good 0-1" mic, you can "fudge" the barrel slug measurements on a Ruger because the grooves are fairly wide and allow some "overlap" measurement, if you very carefully rotate the slug between the anvils and measure the high spots on the groove impressions of the slug, then compare partial to complete barrel slugs, that will tell you plenty.

Go back over my list of things that can cause leading, and dope out the gun dimensionally. It takes about fifteen minutes to evaluate a revolver's dimensions. I do the partial and total barrel slugs, slug the throats, do a "daylight" test of sized boolits in the throats, see how big a boolit will chamber, pull some boolits and measure them, then take a swag at what to load and go shooting. You're right, this IS supposed to be fun, and it is, if you just work out a simple algorithm for checking the gun's dimensions, trying some loads, and adjusting the load and/or gun based upon the results.

And remember, like Brooks and Dunn said, "Learned that happiness on earth,
Ain't just for high achievers." It doesn't have to be perfect to be fun, so when you get it close enough for your purposes, stop screwing with it and go shooting!

Gear

[ColColt]

The cure was a bullet that was long enough to have the front driving band inside the throat when chambered. The shorter bullets were laying at an angle in the chamber, when fired the the edge of the front driving band hit the edge of the throat and shaved lead, more shooting and more leading until it was down into the bore.


The Ruger forcing cones sometimes look like they were cut with a rusty step-drill and lead actually rubs off on the rough machine marks, then gets smeared down the barrel on subsequent shots.

These two comments caused a pause in my thinking today as I looked back over the discussion. I noticed after making two dummy rounds-one with the Lee 158 gr RF boolit and another with a custom mold Keith style SWC that the Lee boolit would fit in the chamber with no resistance and would extract easily as well even though both boolits were sized to .359". The Keith boolit, however went in the chamber ok but extraction was more difficult. Apparently as cbrick mentioned above(post #21), the front drive band must be just inside the throat causing the extraction to be more forceful...just food for thought as I trek along this journey.

Gear's assessment of the forcing cone and area just ahead pretty much sums up what mine looks like. there are circular machine cuts in the forcing cone and as the rifling begins it looks like that same circular cut for the forcing cone got into the beginning of the barrel as well creating about an eighth inch of steps, as I call it. I tried in vain to take picture of it but failed. I hope to check out all this next Friday and move on from there. Just thought I'd mention this.

[ColColt]

Today I went to the range with several different loads using nothing but a .359" boolit. These loads were...

5.5 gr of Universal
13 gr of 2400
8.5 gr of AA#5

All the above with the Lee 358-158-RF boolit using ww's and tin.

Another load with the 170 gr boolit from a custom mold, I used 8 gr of AA#5. All these loads still lead just forward the forcing cone. I suspect there is still a small restriction at the barrel/frame junction. All other areas have been checked and accessed so I can only surmise there's a good chance that is the problem. The 9 gr of HS-6 I like did no differently than the others whether I used a .358" or .359" boolit and ww's or a Lyman #2 equivalent.

The boolits are not being resized at the seating step as I've checked that. Groups were short of superb to me, especially the first and third ones, with the largest measuring 1 1/2", if I discount a flyer that opened up that group. Whatever the leading issue is for sure, it's not affecting accuracy, apparently.

At any rate, I thought I'd just update the progress on this which indicated to me there's still a glitch.

[Bret4207]

I think that rough area might be your biggest problem. An investment in a couple boxes of jacketed bullets, loaded fairly warm, might help in that area and the constriction if there is one. Another alternative is to have the forcing cone recut if the rough area is very close to the breech.

[ColColt]

My SP101 is more smooth in the forcing cone and right at the beginning of the rifling than this GP is. I compared it also to the M29 and there is no comparison there. I think in light of all the checks I've done to date and recommendations followed, I'm gong to load about 100 of the Hornady 125 gr XTP's I have in stock and try those for awhile. Not much to loose at this point. I've shot some of these but not many. Mostly this gun has seen cast boolits early on.

[geargnasher]

Good idea. I guess I don't need to remind you to remove ALL traces of the copper before shooting cast in it again afterward! :D

Gear

[ColColt]

Good idea. I guess I don't need to remind you to remove ALL traces of the copper before shooting cast in it again afterward! :D

Gear

Nope-I'm taking Big Bertha(my 44 Mag) to the range next time along with the GP and those jacketed boolits. No lead for the GP at that point until after a thorough going over with some copper solvent. A clean barrel is a happy barrel. Mine gets cleaned whether I've shot 25 or 250...part of old school training I suppose.