Weaver Style adapter for Mark II-F (non-drilled)?

I have a Walmart Mark II-F that has standard 3/8" scope grooves, but is NOT drilled for other bases. I tried a set of 2 pc rings (Weaver Brand) for 3/8" grooves and 1" scope tubes, but it walked completely out of the grooves within 10 shots -- apparently they are NOT made for heavy 4x16x40mm AO scope I mounted.

As an alternative to having the rifle drilled for bases I've ordered a set of 2 pc clamp on Weaver adapters (see URL below).

http://www.straightshooters.com/bsqu...averbases.html

It looks like they will fit the Mark II well and give me full grip on the existing groove length while providing a standard Weaver style scope base. Has anyone tried these?

just put a set on my uncles rifle for a red dot scope. they work great!!

I expect they will fit well but don't see how they would be any more secure than properly made tip-off rings. They will also raise the scope significantly and may make getting your head securely on the stock more difficult or impossible.

I have a Nikon 4x Prostaff on my Mk IIGL and the rings that came with it are quite wide and clamped to the dovetail with one socket head bolt each. They seem very secure but, of course the scope is a bit lighter than yours. Still, I've never heard of any properly fitted rings coming off a standard 3/8" dovetail under a .22 RF's recoil. Are you sure the Weaver rings were aligned properly and not crowded too near the ends of the dovetails?