Scope Base Screw Holes Spaced Incorrectly


December 11, 2007, 09:25 PM
We recently acquired M38 Swedish Mauser at a gun show. Someone had already drilled and tapped it for a one piece scope base, presumably. Two holes in front, one hole in back. I looked around and there is only one scope base made for a small ring Mauser that is one piece, Redfield makes it. When I went to install it the front two screws line up perfectly. The single rear screw is just over half the size of the 6-48 screw hole off from where it needs to be, a lot. Way too much to fudge/force it.

Options I'm considering:

Pack the receiver in clay and MIG weld the existing hole and re-drill & re-tap

JB Weld the old hole and try to re-drill & re-tap. Since the JB Weld will protrude into the new hole I'm going to need to drill I'm not so keen on this idea.

Other options?

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Jim K
December 11, 2007, 10:22 PM
My first thought is that someone drilled and tapped for the wrong mount, maybe for a 98 Mauser. I would try looking for a mount that matches the holes, even if you have to alter the mount a bit for it to work. If that fails, you might be able to go to a two piece base and just drill the second hole in the rear. But without looking at the rifle, I can't tell if that would work, even if the clip guide was ground off.

There are some other ideas, one of which is to forget welding the receiver and weld and re-drill the scope base. That way, if you mess up, you ruin a $25 scope base, not the rifle.

Welding up the receiver hole and re-drilling would be entirely feasible, but I would make it the last resort. If you do that, use heat control paste and a wire that will stay soft and can be blued.


December 12, 2007, 12:07 AM
someone drilled and tapped for the wrong mount, maybe for a 98 Mauser

I had this thought also. Are all the Mauser 98 mounts pretty much the same? The only other M98 I have around has 2-Piece mounts.

weld and re-drill the scope base.

Now why do such simple things always escape me? I'll do this if the answer to the M98 mount question is no.

December 12, 2007, 09:55 AM
Similar question... Any 96 Swede/M38 rear bases that I've seen don't fit the curvature of the rear bridge, with or without the clip guide. The rear base touches on either side with no contact in the middle. Yet when a level is placed across the tops of the bases, they are level and on the same plane. What gives? I would like to find a base that makes full contact for strength and appearance. Anyone adapt 98 bases to Swedes? Will it work? Solutions?

December 12, 2007, 11:19 AM
Their are scope bases made just for the Swed. they are different then the std. Mauser, also their are many discontinued scope bases which this one may have been drilled for, I know I have a Swed. with Herters one piece mount on it and its hole pattern is different then a Redfield.
I would check with Brownell's tech department about the bases.

Jim K
December 12, 2007, 11:47 AM
Mounts for the standard Model 98 Mauser (VZ-24, K.98k, Mauser Standard-Modell) are the same, since the receivers are the same. Some odd wads, like the short action Yugo M48 or the small ring 98's, require different mounts.

Standard 98 bases won't work with the Swedish Mausers due to the different curvature of the receiver rings, and the shorter action of the Swedish rifles. A base that does not fit the curvature of the ring is the wrong base. Sometimes, in a pinch, a base can be adjusted a little by placing emery paper on the ring, rough side up, and rubbing the base on it until a fit is obtained, but there are limits on how much that can be done without misaligning the base.


December 12, 2007, 02:18 PM
I was thinking about getting an undrilled piece of scope rail and shape and drill it to suite my existing holes. I guess this could be troublesome as I would have to do it very carefully to make certain the thing sits properly. I'd have to contour the bottom of the rail to match the top of the receiver. Hmmm . . .

I'm going to try and weld and re-drill the mount I have first. Thanks for the suggestion. :)

December 24, 2007, 03:36 PM
So I ended up welding in the old hole with my wire feed MIG and re-drilling. I also had to add a piece of additional metal to the end of the base to make sure I had enough room to properly drill the new hole. Beveled and welded the new section on and filed it to match the original base.

Not my first weld job, but the first time I've tried to make something look nice rather than simply strong, this is both strong and looks decent. I was very pleased the welding wire took the blueing the same as the new metal and the original base.


December 24, 2007, 04:25 PM
Darn nice job!

Well done!

December 24, 2007, 07:20 PM
:) Thanks for the compliment. It's amazing what you can do with a welder, some files, a drill press, some sandpaper, cold blue and some scrap metal. ;)

Jim K
December 24, 2007, 11:56 PM
Very nice. I think it was smart to weld the mount rather than the receiver.


December 25, 2007, 01:53 AM
I bought an old 03' once and wanted to put a lower profile scope mounts on. After I took of the old scope mounts there were three extra holes under the front and two extra holes under the rear mount. When I took it back to the man I bought it from he said not to worry the mounts will hide the extra holes he made when he drilled the scope mounts. The only problem was my new mounts didn't cover one extra hole. Took a lot of arguing until I got my money back.

chris allen
December 25, 2007, 12:31 PM
I see that you have welded but here are a couple of suggestions that will work ;

You can soldier a screw the right size in the offending hole (one that is too long so you can cut the head off) Soldier it in place ,make sure you don't screw it in too deep,cut it off ,reshape to the recieve ,redrill and tap in the correct postion.

You can do the same thing but instead of soldiering the screw in place use a non removable locktite,then follow the same procedure.

Merry Christmas,

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