Firearm Forums - Arms Locker banner

Need info on Trapdoor problem

2690 Views 3 Replies 2 Participants Last post by  Unregistered
Hi all,

I bought a TD carbine made from a rifle with original carbine barrel and loaded up some 405 gr. cartridges a la Wolf. I used 55 grains of compressed FFg, drilled out the primer hole and used Winchester standard rifle primers, and Lee 405 gr. 20:1 HB bullets. After firing them I noticed a bulged ring around the case at the location where the base of the bullet starts in the loaded case, and the primers are backed out. The cartridges almost resemble a bottleneck cartridge because the neck for the length of the bullet seems to have not swelled like the rest of the cartridge. After re-sizing them there is a scribe type line in the brass where the bulge was. I'm afraid these cartridges will seperate if fired again. The chamber has a narrow ring inside corresponding to the location of the bulge in the cartridge.

Is there anything that can be done short of a replacement barrel? Is 55 grains compressed too much? Should I go to Magnum primers like I use in my 500 gr. .45-70's I use in my M1884 Springfield rifle?

Any help would be appreciated as I can't afford a new barrel right now and don't want to hang it on the wall.

Thanks in advance! John
[email protected]
1 - 4 of 4 Posts
45-70 used to mean 70 grs of powder

and the 405 gr was the standard bullet wt, too. Was the bullet dead soft, or was it "hardened" a bit, by tin and antimony? that would increase bore friction, and maybe increase chamber pressure. I have no idea about black powder. Is the barrel wall thick enough to let it be bored out and relined? I'd back off the load and try that. Is the bore pitted? Clean it really well, and look at it carefully. Pits both increase fouling and hurt accuracy, they can raise pressures, too. It's not like it's a serious gun, after all. So why not just back off on the load. I think that there's some smokeless, or at least, non corrosive powders available today.
Hi Andy,

I solved the problem last winter. I sent the barrel and receiver to Phil at S&S Firearms and traded it for a correctly cut and turned down tapered rifle barrel with new front sight. The original carbine barrel was ringed before I bought it in the first place, but it had a dark chamber and I'd never seen nor heard of a ringed chamber before. I have heard of bulged barrels, though. Anyway, my loads work just fine in this unringed chamber.

Thanks for replying with your ideas, though.

John L Ellis
sorry I got here so late, but I tend to

think in terms of minimal money spent, especially on items that are merely toys.
1 - 4 of 4 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.