what is the twist rate on 15 in bbl 22-250? mine won't shoot a 64 gr sp bullet on top of 34 gr 4064 less than a five in group. bbl is factory and new. i have trimmed cases and weighed each charge. my 308 holds .75 at 100 but this turd won't group at all. i think that the bullets are too heavy for the bbl twist and lgnth. any opinions will be welcome. going to try 3031 powder and 50 gr sp to be sure it is the load and not the bbl itself.
