Sorry, I was trying to add pictures, but couldn't. The box is green with Remington in red and the end has 223 Remington(5.56 mm) 55 grain metal case index 5223. Thanks!!
That would tell me they are military, or at least the brass is. Could be commercial usage of military production over run, but an over run of 5.56 brass in 1967 doesn't seem to make since with VN heavily ramping up at that time. Are the primers crimped in?
I doubt they are collectible. The vast majority of military 5.56, 55 grain ammo, in that period was made in the Twin Cities AAP. Most of that was shot up in SE Asia. If anything, the ammo marked "TC" is more collectible. I observed the machines running since I was stationed on that property as a young EOD soldier. I have squeezed the trigger on many thousands of TC69 and 70 ammo.
All the commercial makers made equivalant 55 grain FMJ ammo from then, right up to the present time.
Anything with a 55 grain bullet is all 5.56 Mil-spec. It is NOT 5.56 NATO since the 55 grain loads were not adopted by NATO. It is safe to fire in a .223 chamber.
The box says the were made in Bridgeport, Connecticut as all Remington ammo from that time. I actually bought these from a police officer from that time. Thanks for your replies!!