Chuck,

Tom is spot on.

In fact in bench style rifles in calibres such as 270 and 300 Winchester that have a conventional chamber cut I found that in general the best accuracy came from both new brass and FLS brass. The barrels were generally set up to have about .003-.004" headspace on new brass ie. much the same as a factory gun. When FLSing the dies were set to duplicate this.

An added bonus of FLS is that you can usually get loads in new brass and FLS brass to shoot to the same point. Quite often the best accuracy with neck sized brass requires a different seating depth to FLS and very often best accuracy with neck sizing requires the bullet to be seated out further. Unless a 375 is in rifles such as CZ or Wby Mark V the magazine usually limits OAL to 3.6" and that is pushing it for the M70.