NATO Military Ammo Box

This is a NATO military ammo box for 7.62mm cartridges. The box is stamped with the military code markings in yellow print. The box is 17 1/2" long, 7 1/2" wide, and 14 1/2" high and has a removable lid with rubber gasket. The closure brackets are on both short ends.
The front side markings are as follows:
1500 CARTRIDGES , 7.62MM, NATO / 1 - M62 / 9 - M80 / M13
FUNC LOT LC L 139575 71 / M62 LOT LC-10-107 / M80 LOT LC-1-203
(LC is code for Lake City Ammunition Plant, L is code for 'linked ammo')
122 AVG WT / 1.3 CU - USE IN M.G. GAU-2B/A OR M134
National Stock Identification Number is 1305-152-3292(A168)
Short side is stamped - 1500 CARTRIDGES 7.62MM (A168) FUNC LOT LCL13975
Lid is stamped - SMALL ARMS AMMUNITION FOR MINIGUN FUNC LOT LCL139575
Box manufacturer unknown but believe it was made circa early 1970's Vietnam War era.