The Maverick-SH is the only beginner shotgun available. Shotguns are a type of gun that don't shoot very far and don't have a lot of accuracy but do a lot of damage with each shot.
These types of guns are meant for close-range combat, as a single shot shoots out many bullets, dealing tons of damage to enemies. The bullets spread out as the shot gets farther, meaning less accuracy. The Maverick-SH is no exception. It may not be very powerful compared to other higher-tiered shotguns, but as a beginner gun, it does its job well.