Throat diameter

[sniper]

Well, after doing some research, I slugged my 357's cylinder throat diameters. And I have some questions.

Surprisingly, they all came out very similar, measuring .3578+-, with one exception, which miked .3581, and, I could have misread the mike. I don't think that is enough to worry about, anyway. My jacketed bullets, all of which measure .3575 drop through the cylinders without problems.

Does lead have some sort of "memory"? My slugging bullets seem to increase maybe .0002-3 after a little while. Actually, i used Hornady swaged 158gr SWCHP for slugging, which may be some sort of alloy, not pure lead.

Now, I am not sure what my barrel diameter is, but it is probably standard, plus whatever wear and cleaning since 1985 has done. Again, probably not significant. Smiths have that wierd 5 groove rifling, and I am not able to buy a special mike, just for that one-time use.

Soooo, will my .358 Lee sizing die do a proper job, or do I need to consider a custom one, closer to .3575? Will that small a difference even be noticeable? I shoot just for fun, but I do enjoy small groups.

Well; I didn't mean for this to go so long, but I thought it was best to ask the experts while it was fresh in my mind. Thanks.

[runfiverun]

358 sounds reasonable, i think i would mike the inside of a fired case
you might could go 359 and be a bit better, but 358 has worked well in
a bunch of my revolvers

[sniper]

358 sounds reasonable, i think i would mike the inside of a fired case
you might could go 359 and be a bit better, but 358 has worked well in
a bunch of my revolvers

Thanks for the suggestion.
What's the reason for miking the inside of a fired case? Never heard of doing that before.
I think I will try the .358 diameter first, then if I need to go bigger, I can always polish out the Lee die.

[Tom Myers]

Now, I am not sure what my barrel diameter is, but it is probably standard, plus whatever wear and cleaning since 1985 has done. Again, probably not significant. Smiths have that wierd 5 groove rifling, and I am not able to buy a special mike, just for that one-time use.

Sniper,

Make a slug from your bore and see if it will drop through the cylinder throats. If it drops through easily or just fits, you know that your throats are at or above your barrel groove diameter. If you have to push hard or pound the slug through, then you know that your cylinder throats need to be opened up to be at or larger than barrel groove diameter.

Hope this helps,
Tom Myers
Precision Ballistics and Records (http://www.tmtpages.com)

[HORNET]

Miking the inside of the fired cae is to see if the chambers will accept a larger boolit. his can be affected significantly by the brass thickness. I had some military .38 cases that wouldn't chamber in a Ruger Security Six with anything over .355 dia. Swapped them to a guy with a Smith.
You might want to check the as-cast diameter on those boolits that you plan to use. IIRC, you said you had an RCBS mold and they tend to cast real close to nominal size. You may not get any bigger than .358 with your alloy.

[45nut]

I made this thread a sticky so I can watch it and transfer to classics and stickies, I like the information gathering in here already.

[Dale53]

Sniper;
Commercial swaged bullets typically contain some antimony and are NOT pure. They do tend to change dimensions after swaging.

Pure lead retains its measurements with no measurable "spring back" after exiting the barrel.

I suggest you, next time, use pure lead (I believe that you will find Hornady round balls for muzzle loaders to be pure lead). I shoot muzzle loaders of various calibers so I often have some pure lead balls sitting around to slug barrels with.

Dale53

[DonH]

Back when revolvers ruled the line at pistol matches, gents in the know would size bullets to fit the throat diameter. This was/is presuming a few things: (a) target velocity loads (b) cylinder throats larger than barrel groove diameter, (c) fairly soft bullet metal. This allowed the bullet to leave the cylinder aligned with the throat affording it the best opportunity to enter the bore straight.
Loading to magnum revolver pressure levels is an emtirely different thing and requires hard(er) bullets In this latter case, bullet diameter should be determined by the groove diameter of your barrel plus a thousandth or so unless cylinder throats are smaller than groove diameter. If this condition exists. whatever the velocity/pressure level, then your choices are to either live with it or have the throats reamed to the desired diameter.

There may be other schools of thought on this subject but following the lead of a previous generation of oldtimers has worked for me. Good luck with that wheel gun.

[sniper]

358 sounds reasonable, i think i would mike the inside of a fired case...

I miked the inside of a half-dozen fired cases... .357 for all, so it looks like everything is in order there. :)

After sizing, my loaded cases look sort of like a boa constrictor that has swallowed a paint can. But I think that is mostly cosmetic, because they seem to work fine.

Would a smaller...say .356 sizer eliminate the problem, and what effect might it have on accuracy? Or is that just one of those try it and see sort of things?

My buddy, who brags about his casting set-up...a steel coffee can on a Coleman stove...says "How hard can it be?"

I think I am beginning to understand how...:) Thanks, everyone.

Update: I bought some .375 diameter muzzleloading balls, and slugged my bore.

Small, big-eyed grandson looking on, and me explaining why I was banging on my revolver. Just like his daddy used to do. It is good to have that happening again, but it doesn't happen nearly enough. :-D He also "helped" me relube some of the commercial cast boolits I have laying around.

Anyway, the slug slipped through the cylinder throats with no problem, indicating my throats are larger than the bore, if I have understood properly.

I think my next step may be: load some cast bullets sized .358, and see what happens. If all goes well, end of story. If not, buy another Lee sizer in .357, then, if necessary, open it up carefully to ~.3575.

Am I on the right track, here? If not , Please feel free to jump in.

[Bass Ackward]

I think my next step may be: load some cast bullets sized .358, and see what happens. If all goes well, end of story. If not, buy another Lee sizer in .357, then, if necessary, open it up carefully to ~.3575.

Am I on the right track, here? If not , Please feel free to jump in.


Sniper,

You're worring too much. You already have 6 custom sizers that mic from .3578 to .3581. Just like back in school when you studied gozintas. If it gozintas the holders for the sizers, it comes out the right size. If you size smaller and pull the trigger, chances are it swells to that size anyway.

But pull the trigger and let professor gun tell you what he thinks first before you buy anything more.

[sniper]

Sniper,

You're worring too much.

Bass: My wife says that, too. I sometimes do get too involved in ballistic proctology. After all, this is supposed to be FUN, right? :mrgreen:

[runfiverun]

now that you know your sizes go shoot what ya got,
if you are getting holes everywhere but on the target, you can start changing stuff.
if they are about where ya want then you can work on your load and bring it around

[LeadThrower]

Sniper,
I went through the same phase with my 357, and followed a very similar path to you at the suggestion of the knowledgeable gents around the forum.

I slugged the cylinders and the bore. Cyl slugs wouldn't slip through bore but bore slug would drop thru cylinders. My lee 358 sizing die was right at 358 (according to my calipers) and the sized slugs required a very light push to get them through the cylinder throats except one, which only needed a mosquito's sneeze to get it to drop through (i.e. one ever so slightly large throat).

Now I'm shooting with fewer variables on the brain. Now its just powder choice, charge, bullet profile, alloy hardness... thank goodness for this support group ... er, ahhh, forum!

[Molly]

Sniper,

You'e got a lot of good feedback above, but let me add my two cents: I've found it to be an excellent rule of thumb to smiply use as large a diameter bullet as you possibly can, without jamming the gun up. True for both rifles and pistols, and will generally be an excellent shortcut to optimum loads. For example:

If you can load a 0.358" bullet and have it drop easily into your chambers of its own weight, try a 0.359" bullet. If that's too big, try 0.3585" if you want to get really picky. Trying to get a finer fit is mostly a waste of time. Elmer Keith once wrote that proper fitting rounds would rattle when you shook the revolver. Don't worry about throat diameters unless you have a very old revolver. In pert' near all modern revolvers, throat diameter will be between chamber and bore diameter, which is the main thing you need for accuracy and reduced leading. (My .357 rounds look like a snake that swallowed a section of fence post too, from the large dia bullets. They still shoot like a house afire. I've kept them on a paper plate at 200 yards, shooting from the sitting position. I'm not sure I still can, but I can come close enough that nobody who has seen the test will have a lot of interest in sticking his head up at that distance if I'm really annoyed with him. FWIW, my favorite all-time 38 / 357 bullet is the Keith 358429. I've never found a load it wouldn't shoot well, unless someone was trying to get magnum ballistics with a fast powder. Fast powders and soft bullets are for plinking and target loads, period. Use slow powders and hard bullets for everything else.

With rifles, size to as large a body diameter as you can chamber. If you'e using an Ideal design, bump the bullet or beagle the mold until the bullet nose is almost too big to go into the muzzle.

You'll find that loads that use as large a diameter bullet as possible will be a lot more reliable and consistent than bullets sized to bore diameter, and a lot easier to get good results with too.

HTH
Molly

[exile]

Hello, I realize I am getting off topic here, but Molly mentioned the Lyman 358429 as a favorite bullet for the .38. My question is, have you found an accurate combination with that boolit, .38 special cases and Unique? If so I would love to hear about, and again, if I am getting off topic and that is rude, I apologize, I am new to the "cast boolit" forum.

thanks, exile

[Molly]

...Molly mentioned the Lyman 358429 as a favorite bullet for the .38. ... have you found an accurate combination with that boolit, .38 special cases and Unique?

Short answer is no. I haven't used Unique in anything but autoloaders (mostly 45ACP) in years. But yeah, Unique can be used for both light and moderate loads. These faster powders are only good for relatively light loads with cast boolits. If you try to duplicate (or even approach) factory loads with it, you can get a lot of leading, because the pressures and flame temperature will be excessive. For plinking and NRA type target work, I use 2.8g to 3.0g Bullseye. For hunting and long range target work up to about 400 yards, I generally use Keith's recommendation of 13.5g of 2400, but I've noticed that 12.5g is notably easier on the gun and it's pretty hard to tell the difference in the field. H110 is a good powder with the same charge weights. I always use a heavy crimp in the front (crimping) groove. Alloy is generally wheel weights, cast up during the winter and loaded and shot in the summer, so they've age hardened and stabilized. Alox / beeswax lube, sized 0.359". Neither of these will leave any leading: I generally don't HAVE to clean my gun until the holster wear forces me to reblue it again: A well judged drop or two of oil and wipe the residues off the cyclinder is all that's really needed.

The bullseye load has a pretty limited range; something like mebby 350 or 400 yards max, and even at that you have to aim at something like 35 or 40 degrees of elevation like your pistol was a hand-held artillery piece. I was once enjoying a plinking session on private property with some friends, which took place on a long pool in a mountain stream. It was a while back, but as best I can recall, that was the ultimate range where we could see the splash of a bullet's impact. All we had were the little popper loads, but we started to challenge each other to hit smaller and more distant targets - mostly rocks or stumps on the edge of the water. We finally ended up shooting far beyond anything you could hold over using the sights. I recall trying to aim by centering the rear sight on the middle of the six inch barrel, and putting the rock on the top of the front sight - and even that kind of angle wouldn't get me all the way out there. The trick was to line up the sights normally, but aim at something like "one blade width past the end of the third branch of that tree" and watch for the splash. That's how I slowly walked the slugs onto a rock in the middle of the stream rapids at the far end of the pool. Once I had the aiming point pretty well figured out, it was remarkable how consistently I could hit that darn rock, or at least get a splash beside it. When I was out of ammo, I decided to walk down and see how big the rock was, and how often I'd actually hit it. The rock turned out to be the size of a washtub, and it had a lot of lead smears on it. Interestingly, I also found some of the 'near miss' bullets alongside the rock. The water was only about knee deep, and crystal clear, so it was no trouble to pick them up off the bottom. They were completely undamaged, showing how little energy they had left at that distance, but they were still accurate.

I've used the 2400 loads for long range mostly in old strip mines, where you can see the dirt thrown up by the impact. Sure shoots a lot flatter that the bullseye loads. I've never shot a deer with it, but a PA Game Protector friend asked for some to keep on hand for deer that had been hit by cars and not killed outright, but were too injured to recover. The Game Protectors have to put them down, and he was trying out some different guns and loads. He reported back that it seemed roughly equal to a 30-30 in putting them down at close range. Sure is deadly on coons, coyotes, and the like.

The 2400 load is accurate enough that it's no problem for a decent shot to keep the slugs in the chest of a siloutte target at 200 yards as long as you have a steady rest. Ed McGivern knew what he was talking about when he said that a good man with a 357 could keep a rifleman of average skills pinned down at up to 600 yards (obviously assuming an accurate load).

Over the years, I've tried just about every powder I could get my hands on that were even remotely appropriate to 358429 in a 38 Special case. (I use a S&W Highway Patrolman whose cyclinder is just a trace too short to use the 358429 in 357 cases.) I've used everything from Bullseye to IMR 3031. (Got a LOT of unburnt powder!(VBG)) I've even used FFFg. While the results varied quite a bit in effectiveness, residues, etc, I don't recall any of them being inaccurate. This simply isn't the case with most other designs. I personally attribute this to the longer body length on the 358429, but haven't really proven that one way or another. Some of the newer designs with a large meplat MAY be as good, but if I need more than 358429 will give me, I'll break out one of the 44's. I've gotten rid of all my other 38 / 357 molds except for a dinky little collar button slug for indoor shooting.

Sorry I can't give you a favorite load with Unique. Select any reloading manual recommendation that isn't near the top loads. Cast them out of a reasonably hard alloy and size as large as will chamber easily in your gun. If it doesn't shoot better than you can, then you're either a darn good shot or your rear sight is loose.

Hope this helps.
Molly

[exile]

Fascinating information Molly, thanks. I have been reloading for a couple of years, but confess I have never used anything but Unique. I guess I am cheap, poor, inexperienced in reloading or all of the above. There is so much to learn about reloading, shooting, and cast bullets. Sometimes it boggles the mind. I have quite a few reloading manuals, but getting opinions helps to narrow down choices without buying all the different components myself. yes, this was very helpful, guess I am going to have to buy some 2400 powder. Thanks, exile.

[Molly]

Fascinating information Molly, thanks. I have been reloading for a couple of years, but confess I have never used anything but Unique. ... I have quite a few reloading manuals, but getting opinions helps to narrow down choices without buying all the different components myself. ... guess I am going to have to buy some 2400 powder. Thanks, exile.

You're wecome, Exile. Your earlier message didn't mention what kind of load level you were wanting, so I tried to cover the field. If my response was too wordy, that's why.

2400 is a great powder for heavy loads. It's a modern version of the old SR80 (now discontinued), but it does have two minor drawbacks: It doesn't measure badly, but neither does it measure as uniformly as ball powders. Also, it's prone to leave more or less unburnt residues unless the pressures are near max. H-110 is very slightly faster in my experience, leaves much less residue to get under the extractor with less than max loads, and measures like water. Check the latest manuals, but I typically drop 12.5g of H-110 for casual use. I'd personally regard 13.0g H110 as about top, and 13.5g as uncomfortably hot in my gun. Your gun? Well, that's your judgement. A lot of things can affect pressures, and all I can tell you is to watch your primers and case expansion.

And please don't get the notion that I'm bad-mouthing Unique. It's not a bad choice for someone looking for a general purpose pistol powder. It's not quite as good as Bullseye or Red dot for light loads, and not as good as 2400 or H-110 for heavy loads: But nothing is perfect for every possible application, and Unique has the advantages of clean burning and a decent range of applications.

[45 2.1]

2400 is a great powder for heavy loads. It's a modern version of the old SR80 (now discontinued), but it does have two minor drawbacks:

Hmmm, most stuff i've seen in older manuals and data lists SR4759 as the upgrade of SR80.

[Molly]

Hmmm, most stuff i've seen in older manuals and data lists SR4759 as the upgrade of SR80.

Well, I'm old, but not old enough to have used SR80 myself, so you'll just have to take the following FWIW. But I do know that Keith used SR80 for most of his hot load development, and abandonded it for 2400 when that became available. I've not used SR4759 much, but I suppose it could be possible. Hmmm. Might also be possible that SR4759 was recommended as a replacement for SR80, a sort of functional equivalent rather than an upgrade.

I was writting from memory, and could be wrong about that aspect, but I didn't say 2400 was an upgrade. I said it was a modern equivalent. I was only thinking in terms of where and how it's used. Sorry if I've mis-spoken and confused anyone.

Regards,
Molly

[Pepe Ray]

SR80 & SR4759 ====DuPont
H2400===========Hercules
Not likely that one would recommend the other.
Pepe Ray

[Molly]

SR80 & SR4759 ====DuPont
H2400===========Hercules
Not likely that one would recommend the other.

OK fellows, here's EXACTLY what I said about 2400: "It's a modern version of the old SR80 (now discontinued)"

I didn't say 2400 was a modern upgrade of SR80. I didn't say they were from the same manufacturer. I didn't say they were interchangable. Nor did I suggest that one company was recommending the products of another. And the topic wasn't a geneology of gunpowder manufacture and technology. The topic was my experience with 358429 as loaded in 38 Spl cases. I assumed my comment would be taken in that context.

I will confess that the statement is subject to misunderstanding, particularly out of context. My mental process at the time of writting - or at least my intent - was something to the general effect that "Maybe I should mention that 2400 is a modern powder that has roughly the same domain of usefulness as the old SR80, in case he comes across some of Keith's old writtings." I was trying to be helpful, not to prepare for a hostile cross-examination on the witness stand.

'Nuff said. I won't add anything further.
Molly

[HABCAN]

Molly, I certainly enjoyed your dissertation on shooting rocks: it duplicates experience with a S&W #17-2 and a #29-2 with the Lyman #429244 on a stretch of the Sheep river many years ago. (My buddies had a #27's with Lyman #358429 on #2400, OK?)

I quickly went from #2400 to WW #296 when it became available: consistent measuring and less apparent recoil for the same terminal effects. Nearly everything I load for now utilizes ball powders and the recommended magnum primers. Unique in my .45ACP experience always was inconsistent in my measures and left too much residue. I changed to WW Action Pistol with complete satisfaction and now it seems to be discontinued. Oh well, there's always #231.

Thank you for a great post: it brought back happy memories!