M40 technical information / Shims/40x Base

[mjmd11]

After years of finding parts it is time to put a few M40 rifles together. All will be 100% original parts , excluding receivers of course. Last two technical questions. (All will be six digti 322xxx's,168xxx's )

1.What size were the shims used under the front two screws of the 40x bases? Were they steel or brass?

2. Were there 40x bases produced with rounded corners? Have one that was supposed to be legit. (the only part whose authenticity I question.)

 

[USMCSGT0331]

USMC M40's weren't issued with shims, people added them if their scope and base/ring setup wasn't getting enough elevation.

40X bases have had squared corners, rounded corners, and squared/rounded corners on the same base. Post photos of your base and the markings, and I'll try tell you if it's legit or not.

 

[DstRflMn645]

And the shims would go under the rear of the base.