[quote]In the 1990 version “LOP” is listed as “REMINTON OFF EQUIP DIV SPERRY RAND CORP” and listed as inactive. This is clearly not your “LOP”. As these codes become inactive they are reused.
Sorry, I meant that in 1990 the “LOP” code was assigned to the “REMINTON OFF EQUIP DIV SPERRY RAND CORP”. The Mil Std indicates that the code was inactive meaning that the DOD had no contracts with this company in 1990. When I checked my 1999 version of the Mil Hdbk it shows “LOP” as assigned to “LOUISIANA ARMY AMMUNITION PLANT”. These codes are reassigned periodically when one company no longer has a contract and the letters fit another company that is active. The Lonestar Ordnance Plant may have once also used this code.
It looked to me as if your two mines date from the 1950s from the lot number, but I could be very wrong since I know nothing about mines. To identify who “LOP” is you need a copy of Mil-Std-1461 (after 1998 it became a Mil-Hdbk) that dates from the time your mines were made.
To better understand the lot number you may want to check Mil-Std-1168 which describes what information is in ammunition lot numbers. It may apply to mines also. My website has downloads available for two versions of the Mil-Std-1168 and also a Navy briefing telling you how to read the lot numbers from various periods. I hope this helps.
I believe the lot number on ammunition always includes this code with is even assigned to Lake City (LC) and other government owned ammunition plants.