TC Black Diamond Issue
 

I have an older model Thompson Center Black Diamond with a wood stock. I noticed recently that after 3 shots I am unable to cock the action. Close investigation showed that the trigger/ barrel appears to have moved slightly to the rear of the trigger tang. In order to cock the gun after 3 shots I have to loosen the 2 screws that secure the trigger tang to the stock and barrel. I can then slide the barrel with attached trigger forward approximately 1/16 inch and then it works as it is supposed to. I tighten the 2 screws and after a couple shots the same thing happens. I took the barrel out of the stock and it looks like there has been some wear in the wood stock on the rear side of the trigger tang. Any ideas on building up that rear spot where the trigger butts up to the stock? I tighten the 2 screws but the recoil seems to allow the barrel with attached trigger to slide back slightly and can see where the trigger actually has contacted the back side of the trigger tang. On the last shot before it won't cock the trigger is hard to pull since the creep distance is less because it is so close to the back of the tang.

I might have figured it out. I stripped it all down and there was a square block attached to the barrel by 2 Allen screws that fit into a cutout in the stock. It looks like the purpose was to provide a lock for the barrel when it was screwed down to the stock. I loosened the Allen screws and slightly shifted that block towards the back and then tightened it all back down. The cocking works Ok now with good clearance for the trigger creep. My ML season is done and the gun is all cleaned up and I'll do some shooting next summer when I hit the range to see if that took care of the issue. When I loosen the main screws a bit there isn't any movement when I try to move the barrel. Hope that fixes it because it has been a nice little muzzle loader with quite a few deer killed with it. I have a second ML but it is a cap lock 54 and I don't hunt with it anymore. Fun and cheap to shoot round balls with it though.

glad you resolved things,
but if you wanted to maybe help prevent things from coming loose again on you, you can remove them screws , clean them well of any oils or likes, and then add some blue or green or even the purple, locttite to them , to help them stay put longer
that should help prevent them from walking out again from either recoil or vibrations

Good point and I'll certainly do that if my fix takes care of it. Funny that this problem came up after owning the gun for close to 25 years and shooting hundreds of rounds through it

well, things do come loose some times over the yrs, it might have been walking out a little each yr and just finally got to the point it was showing a sign you seen
its also why a lot of folks, when they do a good cleaning go over every thing to make sure there tight
as just never know till you check some times, and its a good way to find things other wise might be missed!
at least it was a easy fix, which is always nice

glass bed the barrel lug and pillar the action screws, problem forever solved!