The story is too long, to tell as to how I came upon these today. But i'll say, its been stored in a dry box inside a gun safe for many years.
This 5.56 M1A3 has a head stamp of 1-85 (1985). M1A3 was made up until 1988ish when the M1A4 started into production. So this is some well kept ammo from back in the day. It also happens to be some of the better ammo from its time. Lucky me, beings .223/5.56 is hard to find right now. I bet this stuff is even harder to find, lol.