I agree rab .Had a good blab though with BASC and we may have some solid advice in the magazine in the near future regarding this overlooked issue.My AYA although proofed at 1200,by modern proofing methods is within the tolerance of the more modern 1320 it seems but sadly without sending it down to get reproofed(if they even were wiling to do this) for steel you take a risk.I have a few rhinos here i was putting through the sp-10 but at 48g weight and their velocity at 1400 added on they are apparently too hefty a load for my AYA.Pity ,but i can use them up through the sp-10 i suppose until i've sold it.