AMU box date

Can anyone date this box? I’ll ask the guy I got it from, if he knows, when I see him again.
I looked on the Rem box dating site, and I read it should have four numbers?


A few more pics.

Likely the first half of 1957. Outside the first half of 1969 but doubtful unless it has a child warning under all the brown overlabels. The date code is N21C and “N” identifies the year.


Thanks Lew.


This must have been pre-production ammunition if
from 1957. That would figure with that type of packaging
and labeling, as it is not the box for production ammunition.
Erlmeier-Brandt indicates the cartridge was developed in
1960, but that could have been the year of first serial production,
I suppose. It was developed and made for the Army Marksmanship
Unit at Fort Benning. Brandt only mentions production by REM-UMC and
Western, but it was also made by Federal.

It is found in Wadcutter ball loadings, Proof Loads (with normal RN lead
bullet, which must be feed directly into the barrel, not through a magazine,)
and dummy rounds.

John Moss