I've not heard of basewad seperation AA-HS problems except for 12ga. (T)he problems reported with 12ga AA-HS were in conjunction with PW and Spolar equipment pushing the basewad up during primer seating.
This was my friends personal experience as well. New Spolar press. Once fired HS 12 ga. hulls. Gun doubled when the bottom barrel was fired. Expanded the chamber and mono block of his Kemen. We presume it was a base wad separation which lodged in the forcing cone. This was determined by the smith who inspected the gun and a sample of the shells loaded by my friend on his new spolar. I have heard similar accounts just like ShotgunJones.
