Min Edge Distance - Hole in Receiver

[4570guy]

I recently bought a beat up Mossberg Model 42C (22LR) as a refinishing project. This rifle has a single take-down screw that attaches the stock to a stud that threads into the base of the receiver. The stud also holds the barrel on the receiver.

I had a devil of a time getting the stud out of the receiver and in the process, broke the stud. I ended up carefully drilling out the remains of the stud (from the receiver) and was finally able to remove the barrel. In the process of drilling out the remains of the stud, the hole in the receiver became a bit over-sized. Now to the point of my question --

The existing edge distance of the stud's hole to the front of the receiver is only 0.16". By my rough calculations, it looks like this is near minimum when I consider the SAAMI max pressure for .22LR and assume a mild steel shear strength of 43KSI. I'm concerned about drilling the hole in the receiver any larger as that would eat into what I think is already a minimal edge distance. Could I safely weld up the hole and re-drill? What do you guys think about the edge distance and increasing the hole size to 3/8"?

[S.R.Custom]

Just to eliminate the guesswork and uncertainty, I'd weld & re-drill...

When it comes to welding, I'm somewhat of a hack --I just have a 230 amp AC buzz box-- but what works really well for that kind of thing is that 1/16" Bambi rod available from Harbor Freight in E6013 and E7014. (For working on guns, I like the E7014.) I use it for everything from welding broken tangs back on to filling in screw holes, pits and lettering. Sometimes several weld & file applications are required to completely fill voids, but at 1/16" diameter and 35 amps or so, it's real easy to control, and not real messy. It blues well, too.

[jmsj]

4570guy,
I would weld it and re tap the hole. Be careful about what type of filler rod you use, some can be harder than heck to drill and tap. Sounds like Supermag has good results w/6013 and 7014. If you have access to a tig welder, try tig welding w/a bare 70S-6 rod (bare=non copper coated). Tig welding gives you a little more control and less heat input.
As for enlarging the hole does everything else line up if you do?
jmsj

[4570guy]

I could enlarge the hole with no issue regarding lining things up.

I did some additional stress calculations yesterday and it looks like the "as designed" margin of safety was about 2.0. If I enlarged the hole, the margin of safety drops to about 1.6.

[Bullshop]

I have a related question. Can off center scope mount holes in centerfire actions on the receiver ring be safely corrected this way as mentioned by SuperMag?
I assume that if yes it would be best to first bottom out a screw in the hole then weld the top of the screw, yes?
I have a 1917 Enfield receiver that is in need of help.
BIC/BS

[S.R.Custom]

...Can off center scope mount holes in centerfire actions on the receiver ring be safely corrected this way as mentioned by SuperMag? I assume that if yes it would be best to first bottom out a screw in the hole then weld the top of the screw, yes?

Funny you should mention that... I was working on some off-center holes from a previous mounting of a tang sight on a '94 Winnie just this evening, and that's exactly how you do it.

As for the safety of welding on a receiver ring... With 1/16" Bambi rod (or Tig), the heat is so localized and so brief as to not materially affect the hardness of the metal. Besides, how much weaker than a hole can you get?

For those interested, this is the link to the 1/16" rod I mentioned. The 7014 is the high strength steel rod, and the one I prefer for gun work. It's got a decent carbon content, so it can be heat treated, too:

http://tinyurl.com/25pbg67

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