Would you trust these threads?

[Jethroat]

I'll try to keep the backstory short. Was given this TC renegade from my (step) grandpa's estate. The person who passed it to me I trusted to know what was what, and so I didn't think twice about using the pack of nipples they gave me. A few years pass and I decide to get it sighted in before WI deer season.

On my third or fourth shot, I feel some sort of blowback, I'm dazed for a moment and then realize my hat is 5 feet behind me, the hammer has been thrown backwards denting the stock, and there is no longer a nipple in the gun. I looked and never found the nipple. Yikes, that pack of nipples was for a tradition's or some other brand, and I now have a problem on my hands.

I took to investigating. The tumbler was shattered, and I read about oversized nipples from TOW. I ordered a new lock, and a .005 and .010 oversized nipples. I was able to get the .010 nipple threaded, and I've attached some photos below. Would you trust these threads with a hunting load? Thank you in advance for your thoughts!

P.s. I've already checked a for a squib, and I do not see any bulging

 

[Boomerang]

Traditions uses a metric thread M6x1. I think Thompson Center uses 1/4"-28.

 

[BoomStick]

Threads on gun and nipple have to match. I wouldn't use an oversized nipple unless the drum has been oversized.

The one that took your hat might have been way undersized, else there wouldn't be much thread left in the drum. Most TC are 1/4-28 out of the factory so check to see if that's still the case.

 

[2 shots]

tracks oversize nipples are made to use their oversize taps. they are not self tapping threads.

 

[Stykbow]

I’ve been there @Jethroat. Buy a new oversized nipple, drill and tap to match new nipple. It’ll most likely just blow out again if you don’t.

 

[Jethroat]

Threads on gun and nipple have to match. I wouldn't use an oversized nipple unless the drum has been oversized.

The one that took your hat might have been way undersized, else there wouldn't be much thread left in the drum. Most TC are 1/4-28 out of the factory so check to see if that's still the case.

It definitely was 1/4-28. But that nipple that ejected took "the point" off the threads in the drum. At the time I initially researched (a few years ago, I'm just now revisiting this project) I was recommended to just buy and oversized nipple and thread it in.

I'm just concerned about the thread engagement at this point.

tracks oversize nipples are made to use their oversize taps. they are not self tapping threads.

I did not know that, maybe I should get that tap, so that it does not gall the threads

 

[Phil Coffins]

No, don’t use that nipple and the breech threads are not to be trusted! You need a machinist or gunsmith to do the job or risk losing another hat or far worse.

 

[waksupi]

Looks like grandpa belonged to the "I take the nipple out every time I clean" bunch. This is the results.