Slugging vs. Casting

[huntrick64]

Had quite a bit of lead throughout the barrel of my new Rossi 92 45 colt with 24" barrel. Experimented with various alloys (50/50, ACWW, WCWW) and it didn't matter. Was loading this 284 gr. SWC over 13.5 grains HS-6 (Ruger only). Leading was sufficient enough to effect accuracy after 10-15 rounds. Slugging showed .4515 (and my bullets were sized .452) I decided to firelap with 10 rounds using LBT compound. That improved things so much that I went ahead and did 10 more.

Bright and shiny now and stopped leading except the first 1/2 inch of the breech. Now, with 50/50 bullets at .452 I get about 1/2 inch of leading and with WCWW I get lead throught the whole barrel. I am thinking this is definitely a "fit issue" since the softer bullets would be obturating, but it slugged out at .4515 so that shouldn't be the case.

Yesterday I received the Cerrosafe from FatElk and cast my chamber/breech and the muzzle. Guess what, after 30 minutes the cast measured .452 and at one hour it measured .453! Looks like my slugging wasn't real accurate. This explains the location and amount of leading I was getting. I will jump up to a .453 bullet and .454 if needed. Hope this will fix it.

I think I had two different problems.

1. The bore was so rough it was grabbing lead from the bullet.
2. My bullet was about .001 SMALLER than my bore.

This thing is turning into a real shooter, at 100 yds I was getting 5-shot groups less than 2" when I could see the target.

Will probably not slug anymore as long as I have cerrosafe.

[tbhutton]

Ok, so could you go slowly for us neanderthals and say specifically what materials and method you used for fire lapping?

[huntrick64]

Sorry, I didn't go into that detail because my point was more directed to the fact that my slugging produced inaccurate results.

Disclaimer for those waiting to pounce on anyone or anything:
There is a lot of info on firelapping here and other locations. Let me say right off that it is not the "solve all" and some people are down right opposed to it. I, however only believe in it because it worked for me. Your mileage may vary. I don't want this to turn into a "for" or "against" on firelapping. I have used Veral's (LBT)methods and compound on about 10 revolvers and pistols, 2 .22 rifles, and now this 45 Colt Rossi. I have used it to remove constrictions in revolvers, smooth out chatter marks in everything, slick everyting up to be squeaky clean, and even remove some rust in a ratty old .22. In each case it has either improved accuracy or ease of cleaning and usually did both. I may have been lucky, but it has never made any of my guns worse. I am anal though on it's use and don't just slop it around and expect it to go where it's supposed to go.

I have lived through a bad car wreck that might have killed someone else. I could be killed if there is a next time. If you can't handle these possiblilities then walk.

The process (for the Rossi rifle, a little diffrerent for revolvers):

In my opinion, a key to this process is that the bullets be the right size for the job you want to accomplish. Embedding the compound into a bullet correctly adds about .001 to the diameter of the bullet so be careful on revolvers or you will end up lapping out your throats instead of somewhere else. Also make sure your bullet is perfectly round because you don't want to lap just two spots on your barrel.

On my Rossi I used air-cooled wheel weight bullets that were cast at least 2 weeks ago. Their BHN is 11, I have had better luck with BHN 13-14, but don't have any on hand right now. Use SWC or something else with a large bearing surface, don't use TL bulets.

Roll the bullet (one at a time) in lapping compound between the two steel plates. I have done up to 4 at one time, but have more consistent results doing them one-at-a-time. You have to put some pressure on the plate as you roll it, but not so much that it flattens it or shoots it across the room. Roll it back and forth counting to 100 strokes with back and forth counting as 1. Wipe off the compound and inspect the bearing surface of the bullet. It should appear solid gray (like a fine whetstone surface). If it is spotty, you didn't roll it enough so do 50 more strokes and check again. This is very time consuming but can make the difference between 20 lapping rounds or 50 rounds. Once you know how many strokes it takes to embed your bullets then you can do that to each bullet up to how ever many you are going to use. I would do 20 to start with and maybe not fire all of them.

Take fired (not sized cases) and bell them a little without sizing them. This lets you push the lapping bullets in by hand and not scrape off the compound you just worked so hard to get in there. If you do this before you ever put a lapped bullet in, you will not have to do it again. You do not ever want to put these cases in your dies because that lapping compound will find its way into places you don't want it to go. Dedicate these cases to firelapping or throw them away when you are done. Dont try to clean them and reuse them for normal loads. I used an extra decapping pin to drive out the used primers with a hammer so I didn't size the cases or get the gritty stuff in my die.

Prime the cases and put in about 2.5-3.0 grains Bullseye (or something else really fast). I actually use that smallest Lee dipper ( I think it is .3 cc) and it is perfect. Then tear off a small piece of paper towel (about 1" square) and roll it in a ball. Use a pencil to stuff it down on top of the powder. This keeps the powder against the primer for good ignition. Insert bullet by hand (if possible) and seat to your normal depth using your eye as a judge, not a micrometer. Wipe off the finished round to minimize the migration of that gritty stuff.

Clean the rifle really good getting ALL fouling out. You don't want to lap fouling, but your barrel metal instead. I run a swab of WD-40 down the barrel before starting to lap. I have done it with and without and WITH definitely cuts better.

Do not ever put these rounds in a magazine or clip, simply load them and fire them one at a time. I used acetone and a rag to wipe down the lap-fired cases between firings to minimize the gritty stuff getting into the gun's action.

I fired 5 rounds then totally cleaned the rifle, swab WD-40 and fire the next 5 rounds. Make sure you thoroughly clean it every 5 rounds. I think this is where some people ruin their guns because it is very gunky just after 5 shots. You have to be your own judge on when to stop and it is easy to "over do" it. You will ntoice that after 10 rounds things are a lot more polished. I did 20 total rounds on my Rossi, but keep in mind I also spend about 4 minutes rolling each bullet between the plates. I have had revolvers that took 80 rounds to get the constriction out. Did I cringe putting that many through a new gun, yes. Did it work, yes.

When you think you are done clean it really good then take a very tight fitting patch (on a jag not a brush) and soak it in gun oil. Run it back and forth several times in the bore to make the patch fit the rifling. Then work some JB Bore Paste into that patch and fit it back in the barrel. Now, push it all the way to the throat, but not out into the chamber. Make sure you have a muzzle protector on your rod and start working back and forth about 10 strokes for the first 8-10 inches, then add about 5 inches to your stroke and do 10 more strokes making sure you are going all the way to the throat each time. A cleaning rod stop really helps if you have one. Keep adding strokes and distance each time till you get to the muzzle. Your final strokes will be over the entire barrel. This is basically more of a final polishing rather than a cutting.

I recommend LBT's stuff, but haven't used any other. I would not use automotive lapping compound even though some have. I have done the guns mentioned above and a friend has done a couple as well. I still have half the container left of the LBT stuff so it goes a long ways. Well worth the money.

Pretty long rambling, but you wanted detail.

The accuracy of this gun is now supberb and my bullets are still .001 undersized. Wait till I get bigger bullets!

[Iron Mike Golf]

I am not sure, but looking at your original post, it seems you slugged before firelapping. Then you did a casting after firelapping and the numbers did not match. Is that the case?

[tbhutton]

Sorry to be so late in responding. That is tremendously helpful! Thank you!!!

Tom

[TMenezes]

I am not sure, but looking at your original post, it seems you slugged before firelapping. Then you did a casting after firelapping and the numbers did not match. Is that the case?

That's what was thinking to. I am considering fire lapping my Ruger Blawkhawk and was wondering if I would need to cast slightly larger diameter bullets after that.

[huntrick64]

Sorry for the delay. I did slug before I fire lapped and assumed, based on previous fire lapping, that the dimensional changes with 20 fire lapping rounds would not be measureable with my equipment. So, after reading your concerns, have gone back and slugged again and cast again. There is still .001 - .0015 difference between the two!

Now, I have not removed the action and slugged only from the breech so something could be happening pushing the slug from muzzle to breech, but I can't feel any variations or noticeable constrictions in doing so. My slug is cast from plumbers lead which should be close to pure, I bumped it up in the vise to make sure it was larger than the bore. I am confident that the breech of my Rossi is at least .453 and will start sizing at that to see if it stops the leading. I feel it will and if not I will go to .454.

Regarding your BH, I have done several and, even though I was able to lap out the constriction under the threads, I did not have to increase my sizing of the bullets. I think the dimensional changes occurred only in the constriction area, but then I stopped right before the complete constriction was removed. My process was: I simply corrected the throats to .4525, then lapped out the constriction in the barrel using AC/WW bullets that were .451 prior to loading them with lapping compound, recut the forcing cone to 11 degrees, and sized my bullets to .452. Prior to that work, .452 bullets would lead the first inch or two of the barrel to the point that after 30-40 rounds, the rifling disappeared and so did accuracy. Now, I can fire up to 150-200 rounds of .452 bullets and a simple dry patch knocks out any powder fouling and no leading is present. I am using LBT Blue and BAC and notice no difference in performance between the two.

Hope this helps.

[geargnasher]

Firelapping will wear the throat pretty quickly, that's where the fresh grit hits first. Leading in the first little bit of the bore past the throat is usually due to gas leakage around the boolit before it gets engraved and is able to seal the bore.

I use the term "obturate" in both the way the medical field does and the way it's used regarding field artillery, which means to block or obstruct a passage rather than the way it is often used here to describe pressure deformation of an undersized boolit in order for it to ACHIEVE obturation of the bore.

Firelapping also should cause a degreasing taper, so obviously the breech end will measure larger than the muzzle end, and if slugged all the way through the minor diameter is what the slug records.

Use of a granular filler behind a boolit will usually cure throat leading, and sometimes selecting a boolit with a larger-diameter nose, or simply seating out further to cork the bore earlier in the firing cycle and prevent gas blowby will take care of it as well.

Gear

[huntrick64]

Hey Gear, thanks for the "granular filler" tip, I have never heard of that, but will look into it if my leading continues. My bullet is "long for the caliber" (284 gr. Keith) and I played a lot with OAL. I even went to 1.700 OAL (.45 colt) and they fed OK through the Rossi, but were starting to engrave the rifling just through chambering. This is why I never really felt there was leakage during a "jump" to engraving, but rather a leak until the bullet swelled up enough to plug the gaps. I think when I go up .001-.002 in bullet size this will go away. If not, what granular filler do you recommend?

[barney67]

Not sure cream of wheat qualifies as granular filler, but I tried a couple rounds in my 32WinSpcl after reading about the cleaning benefits with COW. Using 28.7 grains of IMR3031 behind RD 170 grain GC, I'm getting about 1900 feet per second and seeing powder burn residue on the outside of the case necks, shot a couple rounds with 28 grains 3031 and about 1/4 inch of COW, velocity increased 100 fps and no burn residue outside the case necks.