Early REM-UMC .223 Ammo

Greetings, new here to your fine site.
I have a few questions. I have a few boxes of what are obviously early Remington .223 ammo. I’ve found that they were produced from 1959 to 1963. Which of the two boxes are the earliest?
What years were the two types of boxes made?
And can you tell what years the ammo was made by the lot numbers?


Given the 1959 to 1963 timeframe, the lot number beginning with T (first half 1960) is earlier than the lot number beginning with A (first half of 1963).

Thank you very much dArtagnan.
I’ve looked and couldn’t find any info on lot numbers for Remington military rifle ammo on these years production.
Do have a link to this info? Or could post? What does the L suffix stand for?

The first letter is the year, or more precisely it is 6 month intervals so there are two letters for each year, one for the first half and one for the second half. The numbers are the day of the month, and the last letter is the month based on a 6 digit codeword that changes every 6 months and has never been made public. Seldom necessary to date a box closer than to a 6 month interval.

The year codes repeat every 11 years so it can be tough pinning some down precisely. I recall that the dates and box types were in the IAA Journal a few years ago. If you aren’t an IAA member, it is not expensive to join. Back copies of the Journal are available.


Thanks for the info guys.
Is it possible that the box that has the “MADE IN THE UNITED STATES OF AMERICA” fully printed was made for export to be shipped with the Colt model 601 rifles when sold to over seas governments ?