here are the instructions that came with one of my bases . by doing this ; it should help make things solid by filling gaps between the base and receiver . it should keep the base straight and true . it should keep stress off the scope . it should keep stress off the receiver . I think it's a good idea when using a one piece base . if done by using a release agent on the receiver it will come apart with a good rap from a screwdriver handle .
Never done it ? Good idea I guess but I can not say that I have noticed any daylight on any of my mounts but I have no 1 piece rails other than 1 NEAR manufacturing ring mount and I can promise ya that thing is machined properly ! I would say if it needed to be done it's pretty simple! Not sure every application would call for it ?
Bedded or pinned bases lead to a massive reduction in 'zero shifts'.
Look at the screw holes in your bases ... then look at the screw heads... Do they mate exactly? I bet there's a little slop.
Look at the bottom of the bases... and the top of the receiver... do they mate exactly? I bet not...
Then you're going to expect a little friction and 30 inch/pounds to hold that base perfectly atop said receiver... whilst being subject to recoil and a 1lb (or more) scope.... along with truck rides, saddle scabbards, Eberlestocks, and bumps/bruises.... again, I bet not..
I actually have a set of 30mm Talleys curing in some JB Weld on my Rem. 700 .260 right now. I took some pics of the process for a buddy.... I'll make a new post when it's complete.