5.56 or 223 ammo check

[Ga.Dawg]

I came across some ammo with head stamps of LC 71 and some are marked LC 72 in cardboard boxes of 20 rounds on stripper clips. Is this Lake City ammo and will it be 223 or 5.56 and would you have any problem shooting it? It’s all clean and been stored in a climate controlled garage.

 

[Ga.Dawg]

Also what grain?

 

[CTS Tactical]

Lake City in 5.56. I would have to say 55gr since that is what we used back in the '70s.