Hard and fast rules about American 37mm M16 cartridge case markings

[jeff w]

Two things I've learned over the years about American 37mm cartridge cases;
1) Steel M16B1 cases have their markings ink stamped on the side, not engraved on the bottom.
2) Brass M16 cartridge cases have their markings engraved on the body, not ink stamped on the side.

But in less than 24 hours I've seen 3 examples of these rules violated.

Brass;


Steel (1944 and 1943);


The day is still young - I've never seen an American 37mm case with a 1945 date, maybe I'll see one of those too. Going for the trifecta!

 

[M8owner]

Aliens are obviously messing with you. I have never seen such examples either.

 

[US-Subs]

Not to be too negative, but I'd question anything that starts with "Hard and Fast Rules" about any ordnance. General rules sure, but the only rule is that there is always an exception to the rule. Or not? Now I'm confused.

 

[bacarnal]

Must be your age, Jeff (Subs):xd: