military head stamp

[too many things]

I have seen old 30-06 from 1918 a few before. very few in the 20s and 30s but many in the forties, most in the 40s are den42 and then later 44, 46 etc.
I just came across a few SL 43. I don't ever recall a 43 date on any ammo . the rounds are in good shape and have a " button" type primer. and a very light crimp. Primer is rounded not flat like most
anyone ever seen them ?

[Der Gebirgsjager]

Yes. The vast majority of WW II .30-06 rounds I've seen had the rounded primer, and you'll find head stamps for all of the war year dates.

[Outpost75]

SL indicates the St. Louis Ordnance plant, which was operated during WW2 by the U.S. Cartridge Co. It continued in operation through the Korean war and into the mid-1950s.

Barracks tales of SL meaning "Salt Lake" are incorrect, the Utah Ordnance plant used a U letter code.