.38 SPL case + Cast boolit + .357 gun = leading?

[tacotime]

Getting leading by the forcing cone with .38 SPL (not +P) cast and swaged boolit loads fired from .357 Mag revolver. The .358 boolits will hang up when dropped into the cylinder throats. Bore has not been slugged. Leading visible within 6 to 12 rounds.

I know there are a number of possible causes, does the shorter .38 SPL case used in the longer .357 chamber tend to cause leading because of the extra space before the chamber throats?

Is this combo a classic recipe for leading due to boolit base and side flame erosion in the chamber before the throats?

[Garyshome]

Here is some info.

http://castboolits.gunloads.com/archive/index.php/t-142780.html

[GBertolet]

I think your bullets might be too hard. I had a similar problem in a .357, using 38 cases with hard cast bullets. I switched to a much softer 50-50 wheel weight /lead alloy, and the leading disappeared. It sort of defies common logic, but the softer alloy under pressure will expand the bullet base to seal off the cylinder throats and prevent blow by gasses from causing the type of leading you describe.

[runfiverun]

if the 38 cases were gonna cause the leading it would be before the forcing cone.

[mdi]

I don't think the shorter .38 cases have much to do with leading. In my experience, small, hard bullets will lead every time, but you need real measurements ("hang up" is not a measurement). Slug, use pin gauges or expanding tip ball gauges and get a real measurement. Size the bullets to the same size as the throats and you have the best starting point. I haven't shot any swaged lead bullets in mebbe 20+ years but 99.9% of my handgun shooting is with cast lead bullets, and a properly sized bullet is more important than BHN and lube (you can shoot leading free with a good fitting bullet and a so-so lube, but even an excellent lube on an ill-fitting bullet will prolly lead). Start with bullets sized correctly and go from there. Any more leading and you can look for specific reasons...

[Char-Gar]

Here is your problem in a nutshell:

Your are not giving the charge holes of your cylinder a through scrubbing with a bronze brush and good powder solvent each time after you fire your revolver.

How do I know that is your problem? Because what you describe won't happen if you do. Some of this stuff is pretty damn basic. Whoever told you that you didn't need to clean your revolver on a regular basis was wrong! Shooting 38 Specials in 357 Magnum cylinder has been done for generations for many millions of rounds and if you don't clean the cylinders, you get what you got.

[MT Gianni]

Leading can teach you a lot. Leading near the muzzle end is probably from running out of lube, near the rear of the bbl it is generally fit. In the chamber is where you would lead if it was the shorter cases. Swedged bullets are generally soft and reacting to a build up on the cylinder throat. As stated by CharGar cleaning will prevent the leading.

[Char-Gar]

Leading can teach you a lot. Leading near the muzzle end is probably from running out of lube, near the rear of the bbl it is generally fit. In the chamber is where you would lead if it was the shorter cases. Swedged bullets are generally soft and reacting to a build up on the cylinder throat. As stated by CharGar cleaning will prevent the leading.

I have a cup of coffee to bet the OP is calling the taper inside the charge hole leading to the throat a "forcing cone", which as you and I know is not. The forcing cone is in the root/breech end of the barrel and not the cylinder. That is about the only way his post makes sense to me.

I also suspect what he calls "leading" is the normal build up of powder trash and bullet lube that occurs in the front end of a 357 Mag cylinder when fired with 38 Special cast bullets. Just a plain ol dirty cylinder to me. There certainly is no "side flame erosion" whatever that is.

I think the OP's issues is business as usual when firing cast bullet 38 Special loads in the magnum charge holes. I just think the OP has got us off track with improper terminology. We need a glossary of terms on this board :-). It would not be the first time I have seen rather simples issues spin off into orbit due to the wrong terms on this board.

[Tom_in_AZ]

if the 38 cases were gonna cause the leading it would be before the forcing cone.

I agree. Try a softer lead in the slower .38 spl

[rockshooter]

and a nice tool for cleaning the crud out of the .357 chambers is an m-14 chamber brush- the kind with the rachet
Loren

[GabbyM]

I've a Colt Trooper 357 Magnum revolver here. As is typical. No two cylinders in any dimension measure the same. Two of the loosest of the six holes will horribly lead behind the cylinder throat if I use 38 Special loads. Simple solution is I do not shoot 38 Specials from it. Post that I actually run a fat boolit I had Mountain Molds make me for a customers 357 magnum lever gun that was over sized. It's a 170 grain gas checked boolit I size at .359". Load it in 357 mag cases charged 80% with 2400. It would run 100% but lets face it. 357 mag is a harsh mistress. The Trooper is a lightweight 4" revolver.

Some forget that many a poor sole are just stuck with junk revolvers. I was lucky to have a boolit to yield a work around. 357 mag cases are also hard to come by now a days. But sometimes you simply have to feed a gun what it wants.

[44man]

Not me! Swaged boolits are just too darn soft. Some will have antimony but lack enough tin to bind the metals. They are deformed at the cone and most likely skidding rifling too.
Hard boolits do not lead a bore, all you need is groove size or a tad over.
If he is talking the transition from chamber to throats, same thing applies, boolit is slumping to chamber size then tries to transition to throats. The slump fills the gap between the short case and transition.
You can tell a soft boolit is wrong if you get lead on cylinder faces and frame. It blows out the gap.
I don't like to shoot silly putty!

[44man]

50-50 will not lead a bore but I found I need to oven harden to 18-20 BHN. Need to get a grip on the boolit.

[tacotime]

Thanks for the opinions.

The cylinders and bore are cleaned after every 6 to 12 shots, because the lead build up requires it. It requires vigorous scrubbing with the Chore Boy copper around a copper brush to get the lead out. That is not powder residue. The gun is clean at the start of firing. Still leads up.

The cylinder face and frame are not unduly leaded up.

Also, I know the difference between the throats and the cone.

I am not sure you can get much softer commercially than the Speer swaged bullets or much harder than the Laser Cast ones. All .358 and all lead up with non +P charges.

To restate the question, it is whether .38SPL with cast bullets fired in .357 are highly proned to leading because of the extra open chamber ahead of the throats, and not necessarily just with this revolver.

[Char-Gar]

Thanks for the opinions.

The cylinders and bore are cleaned after every 6 to 12 shots, because the lead build up requires it. It requires vigorous scrubbing with the Chore Boy copper around a copper brush to get the lead out. That is not powder residue. The gun is clean at the start of firing. Still leads up.

The cylinder face and frame are not unduly leaded up.

Also, I know the difference between the throats and the cone.

I am not sure you can get much softer commercially than the Speer swaged bullets or much harder than the Laser Cast ones. All .358 and all lead up with non +P charges.

To restate the question, it is whether .38SPL with cast bullets fired in .357 are highly proned to leading because of the extra open chamber ahead of the throats, and not necessarily just with this revolver.

The answer to your question is no. The extra length of open chamber does not promote leading. You source of leading is to be found elsewhere. Possible causes are;

Alloy to soft
Bullet not the right size
Ineffective bullet lubricant
Rough forcing cone in the barrel
Micro-burrs in the barrel.

I will add that some folks new to shooting cast bullets have unrealistic expectations. Jacketed bullets only leave power trash and a faint wash of metal in the barrels. Most cast bullet loads will leave powder trash, bullet lube and a faint lead wash in the barrel. If it can be brushed out with a dozen or so fore and aft strokes with a brush, it isn't leading.

Those Speer swaged bullet will roll snake eyes much past 750-800 fps in most sixguns. I don't find them very useful.

[mdi]

I agree. Try a softer lead in the slower .38 spl OP's first post mentioned using swaged bullets...

[telebasher]

Best use I have found for swaged boolits is to mix with wheelweights 1to1. Cast, lube, load and shoot as needed.

[greenwart]

44man what are the temp and time you use for 18-20 BNH. I usually use 450F for 45 minutes to get rifle bullets hardened. is your temp in the mid to upper 300's?

[Blackwater]

You've been given some good advice. FWIW, all I can add is that if you shoot cast, sooner or later you'll wind up finding good use for the Lewis Lead Remover. I used to shoot with a pistol team and was issued 1,000 rds. every 6 months of the nastiest, dirtiest, grimiest WC's you'd ever imagine putting in a gun. I actually was hesitant to shoot them. They'd leave the chambers and bores and forcing cones, and anything else they touched plated pretty good. I think the problem was the lube. As far as I could tell, it must have been made from cow chips. At closer ranges, they shot well enough to benefit from, despite their lack of quality. It was PPC matches, which aren't very demanding at all. I got a Lewis Lead Remover and cleanup back to bare bore tookk less than 10 minutes, and was MUCH easier. They're very handy if you shoot .38's in .357's. You might want to consider getting one. I think it's Lyman who makes them now, but can't trust my memory, so someone will have to confirm/correct me on that one.

[coffeeguy]

There are quite a few variables; two which I didn't see mentioned here are timing of the cylinder and expanding/crimping of the case during loading. If the timing is even slightly out of kilter, you'll get lead shaved off the bullets as they enter the forcing cone, but this would happen with both 38 SPL and 357 Mag loads.

Too aggressive of a roll crimp, along with certain loading practices such as not flaring the case mouth enough, will actually result in cast bullets being shaved or swaged slightly undersized as they are loaded into the case, fired, or both. And that's a real possibility as you adjust your expander and crimp dies between 38 SPL and 357 Mag loadings.

[tacotime]

I'm actually using an "oversized" expander plug to combat any swaging, and a very minimal crimp.

Timing is fine, no lead shaving seen.

The old 2.5 in. Mod. 66-1 shot a fine group of one ragged hole off a hand rest at 20 yards using 3.7 Tite and the swaged 158 pill. Might be a tad hot for swaged, though 3.5 Bull with same, shoots pretty clean. This gun had been a policeman's friend since the 1970's until recently. Had plenty of outside wear, but still solid inside.

Really just wondering about that extra distance in an oversized chamber going from the case to the throats... seems like enough space to burn past the base to the sides of the boolit...

[MSD MIke]

The real way to answer the question is to load some 38 special level loads with the same bullet in .357 brass and try it out in your gun. If the leading is gone we have something to think about. I have shot many thousands of 38 special cast loads in .357 revolvers without an real problem. However, I have also had issues with flush seated 38 wad cutters leading .357 revolvers at 750 FPS. I then seated the bullet out far enough to enter the throat and adjusted the load to achieve the same velocity and viola, no leading for as many rounds as you want to shoot. I have also had similar results with SWC loads going from 38 to .357 brass. Same velocity, same bullet. Leads in 38 special brass but not .357 brass. My personal opinion is that the base of the bullet gets worked over pretty good while making the jump from 38 brass to .357 throat. That and the bullet is supported and centered when it slightly enters the throat. For the record the leading problems extended into the first part of the barrel just past the forcing cone on these revolvers. The offending guns were with the accepted .358 throat and .357 barrel dimensions with proper fitting .358 bullets. So, while I generally agree that 38 special brass in a .357 revolvers isn't a problem I own a couple of exceptions to that rule.
If your gun and ammo is dimensionally correct them I would encourage you to try the .357 brass loaded to a similar power level as your 38 special load.
Oh ya, clean your gun:)

Thanks
Mike

Thanks
Mike

Mike

[h8dirt]

Have you checked for thread choke? In my experience, the constriction it causes is often the root cause of leading at the breach end of the barrel. It's usually more prominent in the larger calibers but it's a variable worth considering.

[tacotime]

Those last two made good sense. I will check for thread choke and compare some side by side .38 and .357 brass with very similar loads. I have seen some thread choke before and fire lapped, another gun though.

[Ken in Iowa]

I have a cup of coffee to bet the OP is calling the taper inside the charge hole leading to the throat a "forcing cone", which as you and I know is not. The forcing cone is in the root/breech end of the barrel and not the cylinder. That is about the only way his post makes sense to me.

I also suspect what he calls "leading" is the normal build up of powder trash and bullet lube that occurs in the front end of a 357 Mag cylinder when fired with 38 Special cast bullets. Just a plain ol dirty cylinder to me. There certainly is no "side flame erosion" whatever that is.

I think the OP's issues is business as usual when firing cast bullet 38 Special loads in the magnum charge holes. I just think the OP has got us off track with improper terminology. We need a glossary of terms on this board :-). It would not be the first time I have seen rather simples issues spin off into orbit due to the wrong terms on this board.

What's a charge hole?

[Char-Gar]

What's a charge hole?

The round hole in the cylinder that contains the charge/cartridge case with powder. There are 5 or 6 of them in each cylinder depending on make and model.

[Airman Basic]

The round hole in the cylinder that contains the charge/cartridge case with powder. There are 5 or 6 of them in each cylinder depending on make and model.
Ha. Or 7 or 8 or 9 or 10, depending on caliber and model.

[Ken in Iowa]

The round hole in the cylinder that contains the charge/cartridge case with powder. There are 5 or 6 of them in each cylinder depending on make and model.

OK. I have been calling them chambers.

[prs]

Tacotime, did the Lasercast hard boolits also give the same leading as the swaged softies?

I am wondering if maybe your reloading dies are deforming the boolits in the cases. Pull some boolits and mic them to see. If using a tumble lube, try some NRA 50/50. I use 38SPCL and cast lead boolits in my 357 Python quite a bit and have no leading problem with it and I do not clean it often at all, was not aware that others need to clean often. The boolit I use is one designed for black powder cartridge, the Snakebite Grease Wagon. It may be that huge lube groove that saves me, or the fact the boolit is long enough to mimic 357 mag length for reliable feeding in lever action rifles. Or, that the alloy is air cooled COWW + 2% tin at .358 loaded using M die and light roll crimp. Good luck in your quest!

prs

[Char-Gar]

OK. I have been calling them chambers.

I don't guess it matters. Many years ago when I bought my first new Smith and Wesson it came with literature that called them charge holes. I figured they knew the proper name, so it stuck with me.

[tacotime]

I am not sure I tried the Laser Casts yet in there, but in other situations where the swaged ones leaded, the Lasers usually did too... so can't be sure yet until I get back on the case and do a specific trial.

But I think I stopped bullet deformation with the oversized expander.