Tapping for Oversized Nipple

[Hatchet Jack]

I bought a TC White Mountain Carbine off a guy about 3 years back. Everything looked good and solid with the gun. The gun has some standard wear on the barrel and stock. The 1-20'' twist bore was a little rough when I bought it. I polished the bore up some. It looks a lot better but not great. (I have seen worse looking bores that have shot well.) Other than that everything looked good and the gun looked safe to shoot. I also installed a brand new .250''-28 Treso Ampco nipple. It seemed to screw in just fine.
The first time I shot it at the range the nipple came flying out . Luckily it barely missed it my head as I felt it whisk through my hair. After realizing what had just happened, I looked down at the rifle. The hammer had slammed all the way back and chipped a piece of the stock due to the back pressure from the nipple flying out.
The rifle has sat in my gun room ever since. I decided to get working on it here soon. I plan to fix the stock. Gluing the chipped section back as well as sanding it down and refinishing it.
As for as the loose nipple thread situation. I just ordered some oversized nipples as well as a thread tap to match the threads of the new oversized nipples. The new nipples will be .260''-28. I figured I should be able to fix it myself. Just checking to see if anyone has some experience or constructive advice they can send my way. I would certainly appreciate it.
Thanx

By the way. When I was wrapping things up and pulled the target it had a .50 cal hole dead center of the bullseye. Imagine that....LOL

 

[bronko220002]

I know when I visited various machine shops some of them used helicoils to repair damaged threads.

 

[anonymouscowherd]

. The new nipples will be .260''-28. I figured I should be able to fix it myself. Just checking to see if anyone has some experience or constructive advice

Dont have my WMC in front of me but before drilling and retapping I would check ease/feasability of replacing the part the nipple screws into

Otherwise compare nipple height to standard and order a few extra at same time

I would also see what sizes the mag spark unit comes in or if musket cap nipples are available in your selected size. Might not need/want one now but still having the option down the road it could be a good option

 

[WP79Vet]

Yikes - you had a close call with that one!

Now the issue is whether there is enough undamaged metal remaining in the nipple hole to hold the over-sized thread securely - and the force on the oversized nipple will be greater than the force on the original nipple because the hole will be bigger. I agree with Anonymous - if you can, it would be best to replace the entire part that the nipple screws into.

If you can't replace the part that the nipple screws into, consult a machinist's handbook to find out the drill size recommended for the thread on the oversized nipple, make sure you use that size drill, and make absolutely sure that your drill is exactly aligned with the hole so that you don't hog out too much metal and end up with sloppy (and therefore weak) threads.

As I think about this, if you have to drill a new hole, I'd really recommend that you take this one to a gunsmith. Even though I did a great deal of very high precision, high strength mechanical design and did a fair amount of machining myself during my grad school days, this isn't a project that I would tackle myself.

 

[Hatchet Jack]

Yikes - you had a close call with that one!

Now the issue is whether there is enough undamaged metal remaining in the nipple hole to hold the over-sized thread securely - and the force on the oversized nipple will be greater than the force on the original nipple because the hole will be bigger. I agree with Anonymous - if you can, it would be best to replace the entire part that the nipple screws into.

If you can't replace the part that the nipple screws into, consult a machinist's handbook to find out the drill size recommended for the thread on the oversized nipple, make sure you use that size drill, and make absolutely sure that your drill is exactly aligned with the hole so that you don't hog out too much metal and end up with sloppy (and therefore weak) threads.

As I think about this, if you have to drill a new hole, I'd really recommend that you take this one to a gunsmith. Even though I did a great deal of very high precision, high strength mechanical design and did a fair amount of machining myself during my grad school days, this isn't a project that I would tackle myself.

As of right now. My plan is to chase the existing threads with the tap and see how that goes. I am hoping to get the oversized nipple to screw in and seat snuggly. After that I will shoot off about a dozen magnum loads with the gun in a vise and me behind a barricade with a pull string to protect myself from any flying nipples.

 

[Steverscout]

I bought a TC White Mountain Carbine off a guy about 3 years back. Everything looked good and solid with the gun. The gun has some standard wear on the barrel and stock. The 1-20'' twist bore was a little rough when I bought it. I polished the bore up some. It looks a lot better but not great. (I have seen worse looking bores that have shot well.) Other than that everything looked good and the gun looked safe to shoot. I also installed a brand new .250''-28 Treso Ampco nipple. It seemed to screw in just fine.
The first time I shot it at the range the nipple came flying out . Luckily it barely missed it my head as I felt it whisk through my hair. After realizing what had just happened, I looked down at the rifle. The hammer had slammed all the way back and chipped a piece of the stock due to the back pressure from the nipple flying out.
The rifle has sat in my gun room ever since. I decided to get working on it here soon. I plan to fix the stock. Gluing the chipped section back as well as sanding it down and refinishing it.
As for as the loose nipple thread situation. I just ordered some oversized nipples as well as a thread tap to match the threads of the new oversized nipples. The new nipples will be .260''-28. I figured I should be able to fix it myself. Just checking to see if anyone has some experience or constructive advice they can send my way. I would certainly appreciate it.
Thanx

By the way. When I was wrapping things up and pulled the target it had a .50 cal hole dead center of the bullseye. Imagine that....LOL

I just purchased a barrel from the TC White mountain carbine. I was disappointed to find the nipple hopelessly seized. I'm going to fit it with oversized nipple threads as the threads will be destroyed in the drilling operation i believe there are a few options. Let me know what you go with im curious