If its new brass and the necks are too thick for your chamber then maybe its "pinching".
As you know with the 6.5Saum being a wildcat there are many "spec's" for chambers all similar but different.
I have to turn my necks on necked down 300 Norma Brass but not ADG
I also have to ream the inside necks after first couple firings as I do get donuts.
Best thing I ever did was throw away the neck sizing die.
Bookmarks