I have seen in my experience with loading .223 for over a year and half no big change in accuracy from one headstamp to the next as far as the group size in the target shooting a Savage Mod 12 with a bull barrel. Most loads give me well under a half inch group at 100 yards. If it is over that it was me not the loads, not the rifle. I am the weakest link when it comes down to it.
