memtb,
The "problem" with larger 8-40 screws is their larger threads than on 6-48 screws. The larger threads result in the "unthreaded" portion of the body of the screw (which is what might shear) being just about exactly the same diameter as on finer-threaded 6-48s. But if they make you feel more confident....
Um... NO!
In a properly designed system the shear stress on a screw is placed on the SHANK of the screw, not the threaded portion. While the thread MINOR DIAMETERS of the screws threads you've mentioned are almost the same size they're not exposed to shear stress. They are under tension. A #8 screw has aprox 30% MORE shear strength than a #6 cap screw. An engineer worth his salt knows this though it doesn't surprise me...
Falls under the "you can bullsh!t the fans but ya ain't gonna bullschidt the players". 😉
There is basically no unthreaded portion of a #8 scope base screw to produce a shank. Treaded to the head, stress risers all the way. Forget changing the action for future fitments by changing to #8 holes.
If additional mount strength is required, simply drill & ream for a 1/8" or 5/32" dowel pin. Just behind the rear screw hole in the front base on a Rem 700 SA is a generous area about a half inch long & .300" thick. A perfect place to add mounting strength without changing the action for future mounting applications.
I have additional hints on the process, but utill on board the dowel pin vs. bigger screw concept, those suggestioins are mute.
