Its the standard 223 thats been fireformed in an improved 40 degree chamber, this blows the sides out to an almost striaght taper & the sharper shoulder, you very seldom have to trim an improved case so case life is very good. You also can increase the powder charge somewhat as the shoulder is pushed forward upon fireforming. I have one on an XP100 & its a real hummer on rock chucks. I won't disclose my load as its a little warm but H335 is just one of many good powders in the 223 Ackley Impoved.
Dick
