I was in a club in the 1960's and 70's that received a good deal of AP from DCM. We used to find those steel/tungsten cores around the butts where the rounds had impacted and come apart. My experience was that AP was very accurate... my brother was on the 4th Army ROTC team in the 1960 time frame at Perry and AP was what they used for their long range practice at Fort Hood before going to Perry.