IIRC, GI 30-06 brass had corrosive primers until 1951 when they changed over. Remaining corrosive primers were used until used up so 1951 06 brass has to be suspect as they could be one or the other.
Dunno when LC started making ammo but I do have brass marked LC 42 and LC 43 so at least I would venture a guess as late 1941 or early 1942. I have a couple hundred LC 51 that I have yet to deprime and wondering if they're corrosive as they were made during the transition. Guess I'll just have to break down and deprime them when I find the time.
Paul B.

Our forefathers did not politely protest the British.They did not vote them out of office, nor did they impeach the king,march on the capitol or ask permission for their rights. ----------------They just shot them.
MOLON LABE