What do you use to fill in that rear trench to get a better bearing surface for a rear scope mount/base- wax up the base and use jb weld, devcon? I tried shims, but they don't work as there is a slight radius. I had a 340 Wby that sheared the screws and don't want that to happen again. This rifle (375 H&H) had something like that done- looked like a combo between metal and plastic that fit neatly beneath the base but that cracked in half after 12 years.

A custom base is really the "done right" answer...

That would be nice but I’m taking that rifle to Alaska in October
For brown bear.

I have an older Redfield two piece base on my pre-war M70. It is made to fit down into the "trench." I suspect that many of the older bases made specifically for pre-war M70s would be also.

Use the rear base for a Mauser and relieve the edges so it sits in the bottom of the trench. This assumes you are OK with using a steel weaver base or a Leupold QRW base. You should be OK with this because they are a very good scope mounting system. Hole spacing will have to be altered, most likely. Weaver used to make a base specifically for these (aluminum though). I believe it was a No. 48. Regards, Bill

Thanks to all. I wound up using JB weld for the meantime.

A much more elegant solution.
https://www.ebay.com/itm/32317...2:g:hdUAAOSwEHhauQZV

I have a Weaver 48 base I can sell you if you need it.

Bill Jacobs