If the case shoulder to chamber alignment is responsible for centering bullet to bore centerline via firing pin and ejector spring force explain those loads with bullets seated into the lands? Case/load runout and fl sized so no hyper precision bore alignment via case to chamber as the bullet is being engraved into the leade. Seems to me there is enough case tolerance to allow the bullet ogive into the freebore and leade to center to the bore centerline.
While not popular for hunting plenty of wins and even records both in group and score have been set with loads seated into the lands over the yrs. I have trouble believing firing pin force (which is partially absorbed by primer yield) is over powering bullet engraving or neck tension to center off the shoulder cone.
We also have the sub 0.2 agg with sub 0.100 groups and numerous wins including championships set by a texas BR shooter using, of all things, a standard 30-30 cartidge headspacing off the case rim? IIRC, his loads had bullet jump so no support from either end pinning the bullet or case to centerline.
It seems this evidence taken together supports the theory of the freebore/throat/leade being the constant and thus primarily responsible for bullet alignment not the case shoulder. Not denying it might be contributory in some cases.
While not popular for hunting plenty of wins and even records both in group and score have been set with loads seated into the lands over the yrs. I have trouble believing firing pin force (which is partially absorbed by primer yield) is over powering bullet engraving or neck tension to center off the shoulder cone.
We also have the sub 0.2 agg with sub 0.100 groups and numerous wins including championships set by a texas BR shooter using, of all things, a standard 30-30 cartidge headspacing off the case rim? IIRC, his loads had bullet jump so no support from either end pinning the bullet or case to centerline.
It seems this evidence taken together supports the theory of the freebore/throat/leade being the constant and thus primarily responsible for bullet alignment not the case shoulder. Not denying it might be contributory in some cases.