As opposed to a commie, New York fag who won't defend a person's right to have a salt shaker or a Big Gulp. FUMB!
The U.S. Army has a rifle they call it a rifle, I would call it a cannon; its attached to the front of a tank or a moving vehicle,
Sorry Mikey. I think you've got the U.S. Army confused with Mikey Dukakis. I've never heard of or seen a "rifle" attached to the front of a tank. You're right. You don't know anything about firearms.
Bloomie saw an RPG once and his imagination has been running wild ever since.
The terms "rifle" or "cannon" are used to describe arms with rifled barrels (helical groovers inside the barrel) vs. smoothbore barrels, which are cannon.
I have seen 20-inch naval rifles (20 inch diameter, rifled bore) which many would call "cannons" and be wrong.
It is not at all uncommon for rifles to have 4" or 5" bores, and be 10+ feet in length. Some tanks mount rifles, some mount cannon.
I don't know about that -- didn't the Sovs call their field arty "motor rifle" divisions? It's rifled and gets driven around with motors, so....