The ATI S-BEAM MB3-R in 12 gauge with an 18.5-inch barrel (brand part no. GMB3R) is a pump-action shotgun built for home defense at an accessible price, part of American Tactical’s MB3 series. American Tactical mounts a Picatinny rail on the receiver for optics and tops the barrel in black finish with a blade-style front sight. The shotgun is chambered for 3-inch shells, runs a manual safety, and feeds from a tubular magazine holding 4+1 rounds. Among pump-action shotguns, the S-BEAM MB3-R favors budget-conscious shooters who still want optics-mounting capability.

Key Specifications

• Chambered in 12 gauge with a 3-inch chamber.
• Operates as a pump-action shotgun.
• Features an 18.5-inch barrel.
• Feeds from a tubular magazine with a 4+1 capacity.
• Equipped with a blade-style front sight.
• Ships with a mounted Picatinny rail for optics.
• Runs a manual safety.
• Barrel finished in black.
• Overall length is 39.25 inches.

Frequently Asked Questions

Does this shotgun have an optics rail? Yes, a Picatinny rail is mounted on the receiver.

What chamber size does it accept? 3-inch shells.

Buy the ATI S-BEAM MB3-R 12 Gauge Shotgun

An affordable, optics-ready 12 gauge pump is exactly what the S-BEAM MB3-R delivers. Order it from our Lubbock, Texas gun shop for fast, insured shipping to your FFL.