Is there a particular reason you want the brass headstamped ackley improved? Just curious. I have been using standard winchester brass without problems. Do you have 2 seperate guns, 1 ackley and 1 not? The sharp shoulder on the ackley is pretty obvious at a glance. Just wondering...
It is said that some countries refuse to allow the importation of ammunition which is not stamped the same as the gun with which it is imported. I can't imagine bureaucrats being bright enough to know the difference. But at any rate, if this is your interest, technically since this is an Ackley Improved, it was designed to fit and fire standard .257 ammunition in addition to the improved ammunition. Therefore, if you use ammunition so stamped, it should be in compliance with whose-ever regulations, regardless of the angle of the shoulder.