Leading from cast bullets - treatise.

P95Carry · January 16th, 2006, 09:47 PM

This was from a web site (
http://yarchive.net/gun/barrel/barrel_leading.html ) - but thought I'd reproduce it here, even tho from over 10 years ago. For any folks who reload cast bullets and/or cast their own etc - some useful food for thought IMO. I have used cast a long time but this did cover for me some useful aspects.

Quote:

From: njohnson@nosc.mil (Norman F. Johnson)
Newsgroups: rec.guns
Subject: Re: Severe Powder fowling w/ Reloads
Date: 11 May 1995 22 : 37 : 18 -0400
Lines: 159

David,

# I have been have some trouble with my 357 Mag., 9mm Makarov, and
# 45ACP reloades. I have notices especially in the 357 Mag. some severe
# powder fowling between and ontop of the riflings. I have tried changing
# powders and primers with no luck. Additionaly I am using hard lead
# bullets(Brinell 18) with each load. Here is some load info:

Could you be confusing powder fouling with lead fouling?

Some stuff that you may be interested in:

Bore leading stems from numerous, but usually related causes.
The principle cause I have discussed here before but is one that
is little known or understood by the vast majority of reloaders.
It is gas cutting. A bullet should not be more than .0005"
smaller in diameter than the throat (not the bore) of the gun.
This is true in rifle or pistol. Smaller diameter (lead) bullets
will allow hot gases to rush by and erode the base and sides of
the bullet. Some of the eroded metal plates onto the bore where
it is run over by the bullet.

The best cure to this source of bore leading is to fit the bullet
to that particular gun's throat. Since only a few reloaders have
the ability to do this (throats on recently made revolvers being
typically several thousands oversize) another approach is to try
a softer alloy. That is NOT a typo - a softer alloy will have
more tendency to obturate or "bump up" in the throat and is
often successful in reducing leading, especially in non-magnum
loads.

In MAGNUM loads where bullets already fit the throat and leading
is still excessive, sometimes a harder alloy is the answer -
sometimes. I find that most leading in this case is because of
the choice of powders. It is my experience, speaking of magnum
loads, that one should use the slowest powder that will give the
desired performance to make for successful cast or swaged lead
bullet shooting. My .44 magnums and .45 Colt boomer loads using
W-296 and H-110 give insignificant leading - and some of these are
much hotter than I would be willing to publish here. My bullet
alloy is moderately soft, measuring 12-13 BHN and gas checks are
rarely used.

I have recently been trying pure lead bullets in my 45-70 loaded
ahead of a case full of MR-8700, moderately compressed. To date
I have had no observable leading at 1300 fps in both the Marlin
and T/C Contender. That is with pure lead, folks. If the
buffalo hunters could do it, why shouldn't we?

It is possible the gun, not the lube or the powder is the
problem. Back in the days when I was lube testing I discovered
that a properly finished barrel was far less sensitive to lube
type than one that was rough. This awareness started when I
bought a Virginian Dragoon in .44 Magnum. It had a burr around
the muzzle so severe that the .44 became a .41 when fired. I
started to examine the bores very closely. At the same time I
was shooting a .357 Magnum stainless Blackhawk - and tho it
withstood my dimensional scrutiny it would shoot a few rounds
with particularly good accuracy then lead like crazy! For quite
a time I suspected that there was something inherent in the .357
cartridge that caused leading. Not to worry. When Veral Smith
came out with his theories and bore lapping compounds things
improved a lot!

I have learned to look for five things in particular when having
trouble with revolver accuracy that is apparently being ruined by
leading:

1. Bullets that are more than about .0005" (that is one half
thousand) under cylinder throat diameter - altho jacketed bullets
are USUALLY more forgiving of this sin.

2. A necked down area where the barrel of a revolver is screwed
into the frame.

3. Powder that is too fast for the application.

4. Cylinder throats that are smaller than the slugged (measured)
bore diameter.

5. Rough bores or burrs around the muzzle.

Usually numbers 1, 2 and/or 3 are the culprits. Nos. 4 and 5
less often are the problem but are not insignificant.

Incidentally, I will repeat here an admonition that I have given
before. When trying out a new gun, shoot it with all the stan-
dard stuff first. You may find that those things that you have
come to regard as good or bad do not matter at all and the gun
will shoot to the very best of your capability without putting an
ounce of sweat or a dime of your savings into it.

If I had very carefully examined the bore of the Blackhawk that I
have discussed here before I first shot it, I could have
automatically assumed that it needed the Veral Smith treatment.
Its grooves are very smooth but the tops of the lands clearly
showed tool marks of the boring tool. With properly fitted
bullets (the throats are .455" and the bore slugs at .449") it
shoots as well as I ever will. An exception to my rough bore
theory? - absolutely! But then guns and women often offer some
VERY nice surprises.

If any revolver leads when I am using my old standby home mixed
Alox and beeswax, I assume that it is the system, not the lube
that has failed. So far I have always been able to find the
problem using the above approach. I do not use gas checks any
longer to cure leading problems. I do have a few loads that
shoot better with gas checks, but not because of observable
leading with the same loads sans gas checks.

If lead, rust, or powder residue are the problem:

Scrub the bore with Big 45 Frontier Gun Shop Gun Metal Cleaner.
It will zip that lead, rust and other crud out in a jiffy and
WILL NOT damage your bore.

The Big 45 stuff looks like a stainless steel Chor-Boy and is an
alloy that is harder than lead and softer than barrel steel. Use
Lead-Away or the brass wire screen/rubber plug de-leader
that Hoppe's sells and then the Big 45 scrubber only to see
flecks of lead leave the bore when the Big 45 is used. This
despite the shiny, mirror finish of the bore after Lead-Away.

The Gun Metal Cleaner can also be used to scrub off external rust
without harming the bluing. Its great stuff and I have used it
for years after Skeeter Skelton recommended it in a column long
ago.

It can be had for $3.50 per package plus $.50 (total $4) from:

Big 45 Frontier Gun Shop
515 Cliff Avenue
Valley Springs, SD 57068
605-757-6248

Send check or money order.

Here is a testimonial after I recommended it to a list
subscriber.

# I took your advice, and ordered a bag of that Big 45 gun cleaner.
# Wow, that stuff is the greatest! I deleaded my model 29 in about
# 10 seconds, then cleaned my Colt trooper .357. I brought the
# brush with the tuft of big 45 to our police range on Sunday,
# which runs a public shooting program. We got out one of their
# old departmental guns, really cruddy, and I gave it a shot. In
# about 15 seconds, it was spotless. They plan to order a couple
# of portions for their own use. I really like the product, and
# have to get more for myself and to give my father. Thanks for
# the good tips in the firearms list.

God Bless!

Norm

rocky · January 16th, 2006, 10:37 PM

This is why i switched to a plated bullet to reload. Also , for you Glock and HK users , be careful not to use lead cast bullets if you have a polygonal rifled barrel.

Bud White · January 16th, 2006, 10:42 PM

Been using Berrys and Rainers to get away from lead if someone would make a 440 grain jackedted bullet i would use it in 500 instead of lead but not yet

Resst guns i shoot FMj in or plated

Well of course except 22

rocky · January 16th, 2006, 11:15 PM

yup, the Berrys is what I have been using.

David III · January 17th, 2006, 10:17 AM

I use jacketed or plated in all the semi-autos but have spent a whole lot of time with lead bullets in 44 Magnums (and black powder cartridge rifles -- but that's another world). With the 44s, my answer was to go to a softer alloy (like P95's article says), not harder, and then adjust powder down to where I wasn't running so fast that the alloy couldn't hold together. Too fast, and I found strips of lead along the rifling.
By the time I was finished, I had a load for 240 grain and 180 grain lead bullets where I figured I was at a 44 Special load, about 800 fps. I've used these in five Rugers, two S&W and three lever guns. Just basically no leading. And, I use the same powder load in grains for both weights of bullet, keeping in mind that the 180s would just run a bit faster.
While they work just fine, I shouldn't have just "figured" anything about 44 Special speeds, since when I finally measured some of these, the 240 grains are definitely way over 1000 fps and the 180s are screaming along. At least this does confirm to some degree that sometimes it's a softer alloy. I'd have never, never thought to go softer if I wanted to push a lead bullet at 1200+.

P95Carry · January 17th, 2006, 01:53 PM

As the saying goes David - ''size is everything''!! I certainly agree with matters mentioned about obturation and potential for flame cutting effects - another good reason for not going too fast on powder burn speeds in hot loads.

I do where possible favor gas checks for mag loads - not only for protection from base erosion but as much as anything (tho can't prove it) for the ''scouring'' effect of the copper as it engraves the rifling. Certainly my gas check 357's - using a 158 Lyman cast swc - have never given be much trouble.

January 17th, 2006, 01:53 PM	#6
P95Carry Assistant Administrator Join Date: Mar 2005 Location: South West PA Posts: 25,366	As the saying goes David - ''size is everything''!! I certainly agree with matters mentioned about obturation and potential for flame cutting effects - another good reason for not going too fast on powder burn speeds in hot loads. I do where possible favor gas checks for mag loads - not only for protection from base erosion but as much as anything (tho can't prove it) for the ''scouring'' effect of the copper as it engraves the rifling. Certainly my gas check 357's - using a 158 Lyman cast swc - have never given be much trouble. __________________ Chris - P95 NRA Certified Instructor & NRA Life Member. "To own a gun and assume that you are armed is like owning a piano and assuming that you are a musician!." If a BG dies as the result of pointing a gun at me, then he has merely succumbed to an occupational hazard of being a thug

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

January 16th, 2006, 10:37 PM	#2
rocky Senior Moderator Join Date: Jan 2005 Location: MI Posts: 11,767	This is why i switched to a plated bullet to reload. Also , for you Glock and HK users , be careful not to use lead cast bullets if you have a polygonal rifled barrel.

January 16th, 2006, 10:42 PM	#3
Bud White VIP Member Join Date: Dec 2004 Location: Elsewhere Posts: 17,476	Been using Berrys and Rainers to get away from lead if someone would make a 440 grain jackedted bullet i would use it in 500 instead of lead but not yet Resst guns i shoot FMj in or plated Well of course except 22

January 16th, 2006, 11:15 PM	#4
rocky Senior Moderator Join Date: Jan 2005 Location: MI Posts: 11,767	yup, the Berrys is what I have been using.

January 17th, 2006, 10:17 AM	#5
David III Senior Member Join Date: Nov 2005 Location: Sturgeon, MO Posts: 745	I use jacketed or plated in all the semi-autos but have spent a whole lot of time with lead bullets in 44 Magnums (and black powder cartridge rifles -- but that's another world). With the 44s, my answer was to go to a softer alloy (like P95's article says), not harder, and then adjust powder down to where I wasn't running so fast that the alloy couldn't hold together. Too fast, and I found strips of lead along the rifling. By the time I was finished, I had a load for 240 grain and 180 grain lead bullets where I figured I was at a 44 Special load, about 800 fps. I've used these in five Rugers, two S&W and three lever guns. Just basically no leading. And, I use the same powder load in grains for both weights of bullet, keeping in mind that the 180s would just run a bit faster. While they work just fine, I shouldn't have just "figured" anything about 44 Special speeds, since when I finally measured some of these, the 240 grains are definitely way over 1000 fps and the 180s are screaming along. At least this does confirm to some degree that sometimes it's a softer alloy. I'd have never, never thought to go softer if I wanted to push a lead bullet at 1200+.