i would sneak the die down on some 300 till it gently closes on the brass. load some 270's long and look for rifling marks. back it down till they go away then add a few thou.... start with 72 grains of 22 and see what the brass looks like and head up from there.. the 257 roy and 72 grains of 22 works for the 100. math says 72 of 22 and a 130 in the 300 should be a great starting point. fireform..
load with it touching the lands and work up from 72 grains.... watch for pressure. when your groups open back off on your oal and find the happy medium.... JMO
woofer
