Bad scope mount holes

[Nora]

I brought home a bastardized late war production (byf 45) K98 today. I need a winter project to keep me busy and out of the cold. :popcorn: Whom ever, long ago, drilled the holes for the scope mount with a sloppy drill press (I'm guessing - hate to think of that it was just a hand drill but......) I've drilled many in the past, but used a good drill press and a jig. My question is how does one go about (properly) filling in the holes for a second go around with out compromising the integrity of the receiver or bringing the Swiss into the project?

Thanks in advance,

Nora

[akajun]

Would it be possible to use a small end mill in a sturdy mill or press and a jig to enlarge the hole to 8-40? Only other way I know is to fill the hole with a screw, tig it up, and start over. I dont believe mausers are heat treated.

[waksupi]

Going to a bigger size as was suggested would be the best solution.

[John Taylor]

I have filled some in that were way off with a 1/4"x28 and some loctite then drilled in the right spot. If you want it tough use a grade 8 bolt.

[Nora]

The problem with the existing holes is that they were drilled off center and crooked. The rear mount base is noticeably not in proper alignment with the front mount.

Is any one able to confirm weather or not the Mauser receivers were heat treated or not and give a reference to it?

[Bambeno]

They are heat treated. Holes can be tig welded up then new ones drilled. But it needs to be done by someone with knowledge of how without causing a temper issue on the front ring especially.
Your safer bet for a home fix is to fit a screw to each hole, cut off the head of the screw leaving it 1/8" proud, then lightly peen the screw with a light ball peen hammer. After you peen it down close to the reciever ring file it on down. Then locate your new holes and drill them correctly.

[Clark]

I have over 100 Mausers in various states of being sporterized.
I buy Mausers at gun shows that look like they have good parts.
I get real deals, only to find out later there is something wrong.
Most Mauser deals involve someone making mistakes on the sights.

I try to live with the scope mount holes that are there.
I have tried drilling more holes.
I have tried TIG welding up the holes and drilling new ones.

But the best system is to make a custom scope mount or to "waller over" the holes and countersinks in factory made Weaver mounts, so the mounts can get centered.

I glass bed between the mount and the receiver.
Epoxy is good for 20,000 psi in compression.
I bore sight with a Leupold magnetic bore sighter.

Often times, all I need to do is unscrew the existing mounts, shim with thin strips until bore aligned, and epoxy, and when the epoxy is hard, torque the threads with loc-tite.

I want scopes that have the cross hair adjusted to the center of the scope body to screw onto the rifle and be on the paper. I want the scope mounts to be co- planar and parallel with the bore. That means there is no ring lapping need or wanted. This is easy with a one piece mount, but will take some adjusting with a two piece system.

[swheeler]

Nora if you have the BSquare jig Brownells sells the hardened bushings for 8-40 and 10-32. You could always mount the jig and drop in one of the larger bushings to see if it would clean up the missed holes, if not the filling with a screw and filing it off would work, a little locktite would keep them in place.

[dragonrider]

Had the same problem on my 9.3X57. My fix was to mount two pieces of aluminum using the existing bad holes and then in my bridgeport mill I machined new mounts in place for use with Ruger Rings. You can see that the mounts are off center but the scope is not.

[Dutchman]

The problem with the existing holes is that they were drilled off center and crooked. The rear mount base is noticeably not in proper alignment with the front mount.

Is any one able to confirm weather or not the Mauser receivers were heat treated or not and give a reference to it?

They were not heat treated. They were case hardened. Not the same. You'll have to do your own homework for references.

Dutch

[pathfinder]

I brought home a bastardized late war production (byf 45) K98 today. I need a winter project to keep me busy and out of the cold. :popcorn: Whom ever, long ago, drilled the holes for the scope mount with a sloppy drill press (I'm guessing - hate to think of that it was just a hand drill but......) I've drilled many in the past, but used a good drill press and a jig. My question is how does one go about (properly) filling in the holes for a second go around with out compromising the integrity of the receiver or bringing the Swiss into the project?

Thanks in advance,

Nora

I T.I.G. weld 'em shut. Here is a video of how I do it.
http://www.youtube.com/watch?v=WShQMnUEA9g

[rcbarry]

I worked with a guy who filled in bad holes with a nickel welding rod