Paul I seem to recall that the Mauser custom rifle has a shorter throat than your other sevens, if that's correct, your problem may be due to the short throat not in agreement with those heavier bullets. How does it handle the 100grainers?
My Mauser custom has the standard long throat common to military barrels as this was one of my specifications when I had the rifle build done. Twist is also the standard as originally used in the 7x57 rifles. Lightest bullets I used in that rifle are the Barnes 140 gr. TSX which it definitely does not like. Federal 175 gr. factory shoot reasonably well and Winchester 145 gr. factory ammo are decently accurate but I'm looking for the potential the cartridge has, not the underloaded factory levels. I get great velocity and accuracy from a Ruger #1A with 22"barrel and even better velocity from a Winchester M70 XTR Featherweight with 22" barrel. The Mauser has a 23" barrel.
Paul B.
