Shotgun Nipple Repair

bang_on_sk

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Hi Folks, I thought I'd post this up here and ask a couple of questions.

I bought a muzzleloader shotgun that had an issue with the nipple-seat, so after some long thought, I consulted a machinist on whether or not he could fix it. He milled out the flaw in the nipple-seat, re-threaded it in a larger size, then made an adapter to hold the original nipple. Throw on a bit of loktite and you can barely tell it's been bubba'd.

I'm hoping to get it out this week to try it out with a reduced charge, then build it up and see how it goes!

All in, it cost me a case of beer (instead of the $200-$300 the gunsmith estimated).





 
Interesting. I have made a series of crude taps with the same thread pitch as the original nipple and use them to chase out the original thread until the damaged metal is eliminated. I go up in jumps of about .005" and finish by making a nipple to match the new thread diameter. The advantage of your method is that you can replace a worn nipple using a commercially available nipple

cheers mooncoon
 
I've repaired them the way mooncoon described. Have never made an insert like that. Can't see any reason why it wouldn't work. By all means, testfire it before shooting it off your shoulder. Because the hole goes all the way through, the threads are going to have to take the load, and you really don't want it to blow out.
 
I don't know about Buffalo Arms, but over the years, I have bought nipples from Dixie and TOW in graduated sizes. Just keep going up until there is a good fit.
Have also made nipples on the lathe when necessary. Bit of overkill, a 1600lb lathe being used to make nipples and small screws, but it can be done.
I note that in the OP's photos, there was quite a gouge in the nipple seat. The sleeve dealt with that.
 
Heli coil thread repair is an acceptable and sound solution. It will hold.

I was a bit leery about those, they're not solid pieces of metal, looked too much like a spring and I wasn't sure it'd hold well enough. Plus I would have had to order a dozen or so to get the one I needed.

This is actually a piece of rod that was threaded inside and out.
 
I was a bit leery about those, they're not solid pieces of metal, looked too much like a spring and I wasn't sure it'd hold well enough. Plus I would have had to order a dozen or so to get the one I needed.

This is actually a piece of rod that was threaded inside and out.

we used them on engines with bad threads for the head studs a lot of torque there I don't think id use it in this application though
 
I wouldn't touch a heli coil with a ten foot pole. It would not surprise me if they developed rust between the coils from trapped moisture and fouling. More importantly, the size of the hole from the breach to the nipple base varies considerably between guns. Even though you might consider the pressure transfer from breach to nipple base as acting similar to hydraulic pressure on a piston, a gun with a small connecting hole and the nipple base close to the upper end of the hole would have the pressure on the nipple acting over a much smaller area than if the connecting hole was large and the gap to the nipple base large.

cheers mooncoon
 
I wouldn't touch a heli coil with a ten foot pole. It would not surprise me if they developed rust between the coils from trapped moisture and fouling. More importantly, the size of the hole from the breach to the nipple base varies considerably between guns. Even though you might consider the pressure transfer from breach to nipple base as acting similar to hydraulic pressure on a piston, a gun with a small connecting hole and the nipple base close to the upper end of the hole would have the pressure on the nipple acting over a much smaller area than if the connecting hole was large and the gap to the nipple base large.

cheers mooncoon

While i disagree with the first part about the rust. (If i remember properly they are stainless)

I agree with the rest of it.

Be careful shooting that....it would be no fun to blow the nipple out
 
I don't recall if they are a stainless alloy or not but the fact that they are a spring will allow the fouling to get into the threading of the block which WILL rust.

The bushing is a nice bit of work and a very suitable option. I also like the idea of a larger diameter non standard nipple with the same thread pitch that comes with the special tap that would be needed.
 
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