The 223A is full auto rated for SBRs. Doubt I'll ever own a full auto, but I will probably own a 5.56 SBR upper and it would be nice to be able to blast away without worrying about destroying the can.
Almost went 223P-1, but got a good deal on the 223A since it was a demo unit. That and the 223P-1 is only rated for 14.5" 5.56s.
