The trench gun was a Winchester model 1897 pump action shotgun.

A riot gun is or is modeled on a military M79 40mm grenade launcher. They are designed to fire nonlethal rounds, typically beanbags or riot control gas canisters (CS or teargas).

In Call of Duty, no, but in real life you could, but only if you could hold a gun and a riot shield at the same time.

You need a professional appraisal

simply.

1. go on hardcore search & destroy with a mate. One person uses a riot shield the other uses a normal gun.. hide somewhere decent on the map and the player with the gun shoots the riot shield the player with the riot shield gets XP

The one I have has a 20 inch barrel.