Model of 1916 37mm Gun
September 29, 2014 by Colin Riley

I found the rimmed cartridge case pictured on the right in a box of odd and ends at an estate sale. Measuring about 3 1/8 inches in length, it it somewhat resembles a brass shotgun shell. Actually it is a casing from a Model 1916 37mm gun.
Developed by the French during World War One. The Model 1916 was a small crew served artillery piece used primarily to destroy machine gun nests and the thin skinned armored vehicles in use during the Great War.
Two basic types of rounds were produced, one having a solid projectile which was found to be largely ineffectual and a high explosive projectile weighing about a pound. Fired from a relatively short 29 inch barrel, the muzzle velocity of this cartridge was a pawltry 1296 feet per second, about the same as a 22 long rifle rimfire cartridge.
While the weapon and ammunition was still in use by the U.S both as a standalone gun as well as being mounted on some of their older tanks,when World War Two came around, the gun was entirely outclassed by the armor and weapons fielded by the Axis.

There is a great deal more information here than is usually seen on a case headstamp.
AMLOT 1075-78B
37mm GUN
MODEL OF 1916
LOT 1075-118 PFM Co

Interesting case design with a primer flash tube of 1 inch length
War Department "FM 23-75 Basic Field Manual 37-mm Gun, M1916" United State Government Printing Office 1940 p. 2