Mostly Remington brass and a bit of Winchester. I used powder lube on the neck interiors to try to eliminate the sizer drag, but a lot of them still dragged really hard over the button..I even used my RCBS electric brass prep station to clean the necks inside and clean the primer pockets before sizing. I sized some of the range brass I had also that is mixed surplus, LC, and many other brands I can't identify and they were hardest to pull the sizer through and the least amount of split necks. Haven't loaded those yet as I'm trying to work up a good load for the AR before going all out on loading several hundred rounds.
I went through a few of the containers of range brass I have that haven't been run through a sizer yet and several of the first dozen or so I checked had split necks, so it was a problem with the brass I received as far as I can tell. Never had this problem with 223 brass before even in my 223 AI when fire forming cases in the rifle. I usually run them through the full length sizer the first time and then use my neck sizer only after that with the proper bushings. Very few issues that way so I will check my brass from now on much closer, toss any that seem to have problems, and go back to my routine again. This should keep this issue to a minimum IMO...
Last edited by Sheister; 05/04/21.
