US Projectile, 81mm Chemical, M57
The 81 millimeter mortar round was long and cylindrical in shape with a tapered nose and tail. It had a bourrelet machined on the body near the base of the round which acted as a rear bearing surface and a gas check. There were three raised portions near the nose to act as a forward bearing surface. The nose was machined and threaded to receive an adapter.
Nothing else to see.