If you have a two-piece scope mount, a one-piece mount might help.
A Dampamount may help a little more (and may give extra protection to the scope, if the scope is valuable).
Make sure that there is no oil on the dovetail when you fit the scope mounts and try not to get too much oil on the mounts when wiping the gun, otherwise that will make it easier for the scope mount to creep.
Arrestor blocks are basically a scope mount without the top half. Instead, the top half is usually another dovetail rail (so that arrestor blocks can also be used underneath scope mounts, to raise scope mounts about 1cm higher)
Here's a picture of one of my guns with an arrestor block behind a Dampamount:
http://i459.photobucket.com/albums/q...k/Evo-T003.jpg
JSR (the bbs sponsor) lists various mounts on this link:
http://www.jsramsbottom.com/cgi-bin/...portsmatch.HTM
Arrestor blocks near the bottom of the page (AB3 RAISER / ARRESTOR BLOCK).
Some people use cheap two-piece scope rings as arrestor blocks (without the top clamp screwed on)
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