What is this Proof?

[browningautorifle]

not a factory "Canadian Arsenals Ltd" mark

Sure Brian, you're right. The same factory that produced these marked parts was the one that evolved into CAL, so I don't really see the difference. The very same men that applied the earlier marks now applying the CAL... the whole thing is gone now. CAL would have basicly been started at the same time the FNs went into production.

[Brian Dick]

I think it changed from SAL to CAL post WWII in '46 or '47 if memory serves. There is no difference whatsoever except for the markings.