Miruko 1863 Springfield problem

[muffinman67]

Have any of you heard or experienced this problem I've encountered with a Miruko 1963 Springfield? When live firing, after a few rounds, the breech lifts up from the stock. The Tang bolt doesn't loosen or back out, it remains fully threaded in the trigger guard, so it isn't bad threads on the Tang screw. It lifts up enough to create a pretty decent gap between the bolster and Lock plate. It is necessary to unscrew the Tang screw to push the breech down, and then retighten it. I've never seen this before. Todd Watts Defarbed this for me a few years ago, and without firing it, couldn't see any reason it does this. It's a very handsome weapon, maybe it should be relegated to reenacting only. A shame because it actually shoots pretty decently. Any thoughts would be welcome.

 

[Booner]

I'd have to see pictures of what's going on as I can't imagine what would be causing this other than stripped threads on the tang bolt or trigger guard, or both. Perhaps just stripped enough where the tang bolt can get enough bite on the trigger guards' threads but worn enough to where it can't hold on under recoil?

Later edit--with a little more thinking
I would take the barrel out of the stock and look at the area where the rear of the barrel butts up to the stock, (the breach plug area). I would think that the stock would be cut in such a way that the breach area of the stock would be squared off where it meets the end of the barrel; a 90-degree cut where stock and breech end of the barrel meet so the recoil will be fully supported by the stock and the recoil will be straight back and not up as you are experiencing.

 

[muffinman67]

good thought, I'll look at that. thanks

 

[Tanglewood]

Probably not the problem, but just a thought - make sure that the end of the threads on the tang screw are not bottoming against the top of the threaded lug on the trigger guard and stopping just a bit soon, instead of the head of the screw bottoming against the tang, as intended. That could feel and appear tight against the tang, but not quite be. Easy to check by removing the barrel and tightening the tang screw, it should tighten down into the tang mortise.

 

[Trooper "D"]

Have any of you heard or experienced this problem I've encountered with a Miruko 1963 Springfield? When live firing, after a few rounds, the breech lifts up from the stock. The Tang bolt doesn't loosen or back out, it remains fully threaded in the trigger guard, so it isn't bad threads on the Tang screw. It lifts up enough to create a pretty decent gap between the bolster and Lock plate. It is necessary to unscrew the Tang screw to push the breech down, and then retighten it. I've never seen this before. Todd Watts Defarbed this for me a few years ago, and without firing it, couldn't see any reason it does this. It's a very handsome weapon, maybe it should be relegated to reenacting only. A shame because it actually shoots pretty decently. Any thoughts would be welcome.

I have one of those Indian made double barreled shotguns. I had that problem and it is from the stock being cracked. I still have to repair that thing.
Good Luck and Cheers!