45ACP chamber plating -- Need Help!

[Questor]

I have a problem with what is called by some "Chamber Plating". It occurs in two of my 45 ACPs. These are both target guns and have relatively tight chambers.  My loads are 800fps target loads using 200 grain SWCs. Do you have any ideals of how I can stop this problem? Is it common? It causes failure-to-feed reliability problems.

[Mikey]

Questor - are those loads too light?  Do you have a half moon powder burn on your extracted brass or do they come out clean?  Are these new barrels, er whut??  Mikey.

[Questor]

There is often soot on the outside of the case near the case mouth. One of the barrels has only about 2,000 target loads through it. It's a bullseye gun. Both have relatively tight chambers. Cartridges are within spec for 45ACP.

[Leftoverdj]

Soot on the outside of the case or the inside of the chamber ain't a gun problem, it's a brass or load problem. Your pressures are not high enough to expand the case mouth to get a good case seal. This could be either because your brass is work hardened or because you are using a slow for caliber powder.

Usual solution to hard brass is to anneal the case mouth but I have never annealed anything as short as the .45 ACP. If you go that route, you need to be real careful to heat only the mouth without heating the head. This is done by setting the cases base down in a pan with a quarter inch or so of water in it and heating the mouth with a torch. Likely easier to get new brass.

[Mikey]

Questor - it sounds like you are getting some 'blowback' from light loads that don't seal the brass against the chamber walls and allows gases and powder residue to coat the chamber.  You mentioned your bullet and the velocity but not the powder.  Could your powder be too slow? or is the load a bit too light???  Mikey.

[Questor]

Leftoverdj, Mikey:

I am using Winchester 231 for light target loads. And I am using soft swaged 200 grain SWCs instead of hard cast bullets. I have not chronographed the load.  The intention is that it be about an 800 fps load, but I think it's probably lower than that.  The reason I think it is lower is because the swaged bullets are softer.  The specific load is:

Mixed brass,
Winchester WLP primers,
4.9 grains Winchester 231 powder
STAR 200 grain SWC swaged bullet with external waxy lube on entire bullet

I am in no way dedicated to any of these components, although I would like to stick with some brand of 200 grain SWCs because they make good holes for target shooting. Can you recommend a component combination that is likely to yield a reliable load?

I should clarify that only one of the guns is getting lead sticking to the chamber walls. The other one functions fine with the ammo until about 40 rounds or so, and then it starts to fail-to-feed occasionally. It gets worse the more rounds I shoot.  It typically fails when the chamber is cool.  If I heat it up by shooting a few magazines in sustained fire, it is less prone to fail.  

My previous problems with unreliable loads has been related to overall cartridge length but that does not seem to be the case this time. When I examine the gun after a failure to feed, I find that the cartridge is squarely in the chamber, but the gun has not pushed it in far enough to close the breech. When I push the slide, it closes with just a bit more effort.

I appreciate your help on this. It is very vexing.

[Duffy]

If your getting lead smeared in the chamber sounds like it's melting. Are you getting shaving at the case mouths when seating the bullets that is blowing out into the chamber and then melting with the next shot? Wonder if a bit faster powder like Super Target or similar would help. Might also try Lee liquid alox, I know it's messy but it might give a little extra protection.

[Questor]

Duffy:

Melting is a big mystery in this one. I didn't know whether I'm using a primer that's so hot that it actually melts some of the bullet base. A lot of bullseye shooters use Winchester WLP's, though.  

"Plating" is actually a good term for it. I didn't notice it until I really looked close. It's not up front by the bullet, it's along the middle of the chamber. I don't see how it could get there through the chambering process. It is lead, though.  I've never heard of this sort of thing.

[Questor]

Duffy:

The cases have a good bell on them, and there is no shaving apparent.

[ricciardelli]

Well, I guess I will jump in here...even though I am not a cast or swaged bullet expert.

After reading all the posts, I have to say that I doubt that your load is doing 800 FPs, probably between 650 and 700.

In addition, I would guess that maximum pressure is around 8,000 PSI.

I have to agree that you are not generating enough pressure to fully seal the chamber, and you are experiencing a gaseous lead blow-by.

As a side note, swaged, pure lead bullets, are fine in .22 rimfires, however, I knew a man in California who was getting ready to market some swaged bullets in 9mm, .38 & .357 and .44.  He asked me to test them and file a report.

I went through several thousand and decided they were useless.  In loads light enough not to totally obliterate the rifling in the barrels of the test guns, there was excessive blow-by in the chambers.

In loads that were hot enough to eliminate the blow-by, the rifling was totally useless ... the guns had become smooth-bores!

I actually recovered some bullets and they had NO rifling marks whatsoever.

He never marketed those bullets...instead he melted them down, mixed them with tin and antimony and sold extremely good cast bullets.

[rbwillnj]

Actually, if you spend sometime on the Bullseye-list you would see that that serious Bullseye shooters have a very high regard for Star Swaged bullets, with the most popular being 148 grain HBWC for 38 Special loads, and 185 Grain HPSWC for 45 ACP loads.  The typical Bullseye load for the 185 grain bullet is 4-4.5 grains of Bullseye powder.  

Bullseye shooters tend to use lower loads because they aren't concerned with knock down power, but they are concerned with recovery for timed and rapid fire.  I get some chamber plating too.  I clean it out and move on.   If you go with a higher load, you will seal the chamber, your gun will be cleaner, and you probably won't get the chamber plating....but if bullseye shooting is your game, that may not be the way you want to go.

[Questor]

Thanks for the tips, everyone. I'm starting in my ususal bone-headed inquisitive fashion by doing three things:
1) Increasing the powder charge of my current load by 3 tenths of a grain to see what happens.  The charge will now be 5.2 grains of Win 231.
2) Replacing the powder with 4.1 grains of bullseye, but using a load that is otherwise the same
3) Replacing the powder with 4.1 grains of bullseye and replacing the bullet with a cast bullet.

I've got 100 rounds of each, and that's enough for an initial reliability test for each of the three loads.

[sgtt]

You may even go a little lower with BE.  3.8 works well for me.  May require some "tweaking" of your recoil spring.  Most of the BE shooters I know use hard cast bullets.  15+ brinell.  I think that is too hard for the velocity they shoot but, some of them are High Masters and who am I to argue with success.  I believe that a swagged bullet may be a little soft for an auto.  There is also the old BE trick of putting 1 drop of oil on the first round of each mag...........

Lastly ask some of the BE shooters what they do.  They are usually a great group of people who are more than willing to share their knowledge if asked.

[Questor]

With the 5.2 grain load of Win 231 I no longer get a large amount of black soot on cases.  I fired 100 rounds last night and had no failures.  Apparently you were right about the blow-by being the problem. Thanks for the advice.  

By the way, I got into this pickle by listening to someone else's advice to use a lower powder charge after using 5.0 grains of 231 successfully for years. I had lead chamber plating with 4.7 grains, failures to feed due to dirty chamber with 4.9 grains. So there's a threshold there that is very interesing.

With 4.9 grains, there was a lot of powder residue everywhere. With 5.2 grains the residue is light.

I think this problem is solved, thanks to your advice.

[Louis Farrugia]

With the 5.2 grain load of Win 231 I no longer get a large amount of black soot on cases.  I fired 100 rounds last night and had no failures.  Apparently you were right about the blow-by being the problem. Thanks for the advice.  

By the way, I got into this pickle by listening to someone else's advice to use a lower powder charge after using 5.0 grains of 231 successfully for years. I had lead chamber plating with 4.7 grains, failures to feed due to dirty chamber with 4.9 grains. So there's a threshold there that is very interesing.

With 4.9 grains, there was a lot of powder residue everywhere. With 5.2 grains the residue is light.

I think this problem is solved, thanks to your advice.

HI QUESTOR

I HAVE A SPRINGFIELD .45 acp WITH MATCH  POLYGONAL BARREL I USE 185 CAST HEADS 2 to 1 LINO WITH GOOD FEED AND NO LEADING
I SWAGE TOO, 200g IN .452 DIM USE BASE DISC AND AGAIN NO LEADING
THE POWDERS I USE ARE NOBEL AO 7.2g OR NOBEL A1 5.3g VERY ACCURATE AT 25 MITERS 2" GROPES.

I WISH  YOU AND THE FORUM MERRY CHRISTMAS AND HAPPY NEW YEAR

BEST REGARDS
LOUIS FARRUGIA
MALTA EUROPE