K31 drill & tap mount - now what?

F

FirstFreedom

Moderator
Took Brownell's K31 left-side drill & tap mount with K31 to gunsmith. Gunsmith keeps it 5 weeks. At one point LOSES my mount and orders another one from Brownell's. :rolleyes: Now today tells me:

-Sorry, the steel is too hard; can't do it.
-I broke 3 bits trying to drill it.
-I could try the carbide bits but it still wouldn't help because I don't have carbide tappers in the 10-32 size, and even if I did, the carbide would be too brittle & break while trying to tap on this hard steel
-I could spot-anneal it, but I'm reluctant to put a flame to anyone's gun

So I get it back (for free of course) after 5 weeks, with the mount, and a divot in the side where he started to drill the first hole. :rolleyes:

Now what? What gunsmith can I send this to, who can do it for me? Thanks.
 
I can see his problem. I have never tried to drill a K31 and didn't know they were that hard, but I have had many similar problems with M1903 receivers.

One of the problems is that screw size. 10x32 is a common hardware screw size but an uncommon scope mounting size. Brownells doesn't even list a carbide drill for that size (21), let alone a carbide tap. I suppose the drill and tap could be found somewhere on special order, but they are very fragile and the combined cost would probably be around $60-70, pretty high for one job when breakage is so common (this from a guy who has broken carbide taps and knows how easy it is).

Who can do it? You might try asking Brownells or the mount maker, or wait and see if anyone here knows a gunsmith willing to tackle that job. But I wouldn't hold my breath.

(Don't the ads always make it seem so simple?)

Jim
 
K-31 scope mount

A friend of mine has a scope on his K-31. The mount was a no drill/no tap, and cost him nearly as much (or maybe a little more) than the rifle. Gun shoots sub-moa at 100 yds with Swiss (match) ammo. If you are interested, let me know, and I'll ask him where he got it.
 
Don't the ads always make it seem so simple?
Click to expand...

Yes. Yes, they do. :(

Thanks guys. Yeah, the clamp-on mount goes on the right side of the receiver, whereas the drill & tap mount goes on the left side. I don't know how one can peer over the right side of the stock to see down the scope on the right-side clamp-on mount, if one is right handed, which is one reason I got the drill & tap. But also for sturdiness.

Here's the clamp-on mount.

http://www.brownells.com/aspx/NS/st...x?p=1666&title=SCHMIDT-RUBIN+K-31+SCOPE+MOUNT


I'll fish here for someone who might be able to spot-anneal it with some sort of welding torch or whathaveyou.
 
You can spot anneal the metal by using a piece of drill rod in a drill press with a blunt end and a lot of pressure.
Run the drill about as fast as you can and push the flat end of the rod onto the spot you need to soften.
It takes a while but it will get hot enough to soften.
No lubricant of course.
MSC or any of the tool suppliers will have the drills and taps if you really think you need one in carbide, but it is a loosing battle.
Better to spot anneal.
 
OK. Thanks. I don't have the tools for that. I'm looking for a gunsmith for hire who does have the tools.

By the way, on a completely unrelated subject, anyone want to buy a brand new K31 drill & tap mount, delivered to your door, cheap? Looks like it should work fine. :)
 
I have shot the K31 with the clamp on mount

And did not have any trouble with it. In fact, although it looks "wrong" the only complaint I had was that the rifle I shot had a very thick (feeling) wrist, and kept me from being as comfortable as I would like. My friend has no problem with it, but I prefer a slimmer pistolgrip.
 
I drilled and tapped the model 1911 which is the earlier model of the K31. Yes the steel is hard, but once you get the hole drilled, use a carbon tap so if it breaks on you, you can tap it out instead of worrying with drilling it out. I used 6x48 screws and broke only one tap while doing the job. My carbide drill took care of the holes.

They used some very good steel to build these guns and they were all exceptionally hard through and through unlike the Mausers that were usually case hardened.

I mounted an scope designed for the SKS myself but later switched to a larger scope. I had to make sure to place some mole skin under the scope to keep from scratching it when the brass ejected.

Another option is to use a scout style scope mount and replace the rear sight with the scope mount. I have used one one a Nagant and really like it. Then if you want to you can simply drive the mount off and replace the rear sight and keep right on shooting.
 
I was about to mention that someone here had a scout mount for sale in case you were interested, and to my knowledge it never sold. Turns out it was you. Good luck getting the holes tapped.
 
I've been shooting the K-31 with the clamp-on for several years. I have not found the scope position that difficult to get comfortable with. I do have a problem with empties hitting the scope, but the offset is barely noticeable for positioning when shooting. When I bought my mount it cost more than the rifle. It seems that the rifle prices are going up, while the mounts are going down. I have two K-31's with a bunch of targets with groups between 0.5 and 1.0 inch so I think the mount is pretty stable. Granted, it is still a clamp-on, but a pretty solid one none-the-less.
 
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