What do I have here?

Base is marked as follows:

M82 LS - 79F 308 - 017

OAL - 2"
Case mouth - 0.446
Case base - 0.489
Rim - 0.600

This is actually not a cartridge but a primer or “vent piece” for a 155mm Howitzer. this is used to produce the flash to ignite the main charge which is placed in the breech in cloth bags instead of a brass case.

The “primer” is acutally a firing pin which leads through to an internal primer which stengthens the seal against the very high pressures that it has to contain in the gun breech.

M82 Is the model number

LS Indicates it was made at Lone Star Ammunition Plant, Bowie County, TX in 1979.

79 Is probably the date, I’m unsure about the “F

308 - 017 Is probably a lot number.

Thank you, Falcon.

The letter code after the year indicates the month of manufacture, in this case F = June. A = January, B = February, etc. The letter “I” is omitted since it could be mistaken for the number 1.