When talking bolts of 1/4"" it is more likely to use inch-pounds instead of foot-pound and even use an inch - ounce torque wrench. One can use a foot-pound torque wrench but it's range for that size of bolt is at the very bottom of the wrench's scale and may not give an accurate reading. You need to use a torque wrench that is in the upper 75% of it's range to get the most accurate reading for the torque value required.
I had him bring the gun to my shop for a better look and even though to my eye the threads seem sharp it appears that someone in the past has had the same problem. It appears that they made an attempt to peen the breach to tighten the nipples. I can retap these threads but it seems to be more an issue of the wrong nipple size to me. Here are a few photos of the threads but it's hard to get a close-up in that small of an area.
My thinking is the plugged hole was for a scope mount or something like that, I haven't run a bore scope yet to see if it goes all the way into the barrel, I hope not.
Those are the ones I've used on old shotguns that had badly rust threads.
I already have all the tools necessary to take the threads up to 7x1 mm which is just slightly larger than the damaged ones but thank you for the link.
Yup, my buddy got the gun reasonable enough so fixing it is still a good investment. When he first got it he showed me the peen marks and asked about them, I told him I had no idea why someone would do that guess I do now....
