Australian International Arms - AIA M10 No. 4 Mk. IV

[Peter Laidler]

Or maybe it is designed to have a longer 'throw' during the leverage part of the primary extraction phase. Just a thought.

But going back to 7.62 x54R, it is a very forgiving cartridge case. Even the steel cased ones. I was always under the impression that the base-rim diaameter, length and taper put it at the extremity of its ductility. But I saw a .303" Vickers firing it and the barrel had been chamber-reamed to accept the larger diameter base but forward of that it was plain old .303" form. The gun fired flawlessly and the cases came out totally bulged at the forward end ehwre they'd fire formed into the forward form of the .303" case.

A few had split necks where the ductility of the steel HAD been exceeded but 90% were bulged but........., well, apart from that, OK.

They were making a one way trip so the odd split necks and bulged cases were of no consequence. As I say, the gun fired 500 rounds in 10 - 20 round bursts and didn't miss a beat. I have to say that it shook me but did raise my regard and respect for the 7.62 x54R even further that it already was. A respect I gained while using the PKM.