Rifle Grenade Anti-Tank, Practice M11A2. Lot E-12 MFG 8/1943. this is an inert round no dangerous elements inside it. The actual live rounds were M9/M10 models.
The M9 rifle grenade was an American anti-tank rifle grenade used during World War II. It was derived as a lighter version of the M10 grenade which was too heavy to be fired to an effective distance from a rifle. (The M10 evolved into a rocket-propelled munition known as the bazooka.)
Towards the end of the Second World War, its limited effect against heavy German tanks became noticed. This became apparent when US forces engaged T-34 tanks in the Korean War. It was replaced in the anti-tank role by the M28, an American version of the Energa rifle grenade, which was itself replaced several years later by the M31 HEAT rifle grenade.