I have my shield target loads they chamber and shoot great at 1.250 oal and the bullet just barely crimped I am using 200 gr extreme plated bullets, be powder and my dies are horniday custom grade taper crimp die set. I would have to look at diameter with calipers can't remember right off top of my head. I have ran into a problem when case is flared to much or same thing with crimping too much. I would just make you a dummy round and do a plunk test keep easing in oal till you get the bullet were you need it.