Even if headspace is ok in that National Ordnance 03A3 I wouldn't shoot it. Those folks slapped gov't surplus parts onto el cheapo cast receivers and foisted them onto an unsuspecting public. You couldn't give me one of them. Well you could and I would part it out and toss the receiver in the garbage.

"You can lead a man to logic, but you cannot make him think." Joe Harz
"Always certain, often right." Keith McCafferty