Sir,
civilians call it 223....soldiers always call it 5.56.....its the same for practical purposes without getting into nitty gritty chamber throat issues. Old habits and all on my part for calling it 5.56.......
Ammo is a different story....but anyway. The shell plates I believe will help you. I know I run into these case periodically and when I slide it in the shell holder and the base is bulged out and will not fit into the shell plate, some will just by rotating the case, if not I just pitch it. I simply use the sb dies on once fired military brass the first time then just use regular 223 or my wildcat dies ( I build wildcat ARs )on them from then on. Of course in a bolt weapon neck sizing after fire forming gives you the best accuracy usually
I would try the shell plates from Hornady / Redding first as you are using a bolt weapon and it is much more forgiving to case issues than a gas weapon is. sb dies are tight but you are are already using imperial wax and its the imo the best.
I had a handful of brass and 2 shell holders in my pocket when I stopped at a store checking on supplies. I got to talking to 2 guys about reloading, so I pulled out some of the brass and holders. The first guy said, "You tumbled these in ss media after you sized them." I said yes. "Do you have vains in the tumbler?" Yes, and I showed the picture on my phone. He said, "remove the vains and I won't be beating up the brass like this." I asked why just here at the base and not at the necks. "Don't know, I removed mine and it stopped."
I told him I had a bunch of brass primed that will fit the priming shell holder but not the die set shell holder, what am I to do? "Well first choice is to junk them. If you get them into that shell holder to decap the good primers, you might as well load them, then junk after shot. You may want to lube the whole case when seating the bullet." I asked about using a bulge buster on them. A little talk about that. "I've used a 40 cal followed by a 380 buster."