Help ID This Piece



Do any of the experts know what the piece below is?

I have convinced myself it is a primer for an American artillery shell, it was manufactured December-1966, and is a Model 82 of something which means nothing to me.

Could one of you please tell me what this thing is used for and who made it?




U.S. Percussion Primer, M82 made at Lone Star Ordnance Plant in December 1966.

This percussion primer is used with the U.S. bag type artillery guns/howitzers, 155mm, 175mm and 8 inch. It may have been used with others in the past, but those seem to be the major uses.


Here’s mine :-) Is it loaded with a blackpowder charge?



Percussion primers are typically loaded with black powder. Those intended for case ammunition have enough to ignite the entire smokeless powder charge while those intended for seperate loading have only enough to ignite the black powder igniter charge attached to the bag or case. I believe the M 82 is designed to be used in either fixed or semi-fixed rounds.

It looks as though someone has pried open a couple of the petals on heavyiron’s example. Trying to see what is inside, no doubt.



The top example is fired, causing the petals at the mouth to open.

These do not have a “primer” in the normal sense, but rather a heavy duty hard plunger which is exposed where it looks like a primer. The front of the plunger has a point which hits a more or less normal primer cup to initiate the firing.

The plunger is restrained inside the case by a large shoulder, thus providing a strong seal at the rear, instead of just a thin primer cup.

Here is a drawing, but it is pretty hard to read except in large size so this is a link instead of an image.


Mine is fired so all the petals have opened. We use(d) 105 mm with cased ammo only, all the other artillery (155 and 203 mm) used bagged charges. The 203’s and all the towed 155’s have been retired, but we still use M109’s for firesupport. Mine came in a small collection from an former sargeant in a engineers regiment.



Thank you to everyone for great explanations about a topic I knew nothing about.

Mine is definitely fired. I got it in a small collection of military rifle cartridges and it had been lacquered by the previous owner as well scotch tape labeled “Electric Fuse”. I couldn’t figure that one out. I kept on looking at (what I know now is the plunger) thinking it was an unfired primer and wondering what was electrical about a percussion primer. Now I know “the rest of the story”.

Thanks for all your help.




A true electric primer is very different from the one shown. A combination percussion/electric primer looks exactly like yours except that it has a black insulation ring around the firing plug.