Attaching crap under the barrel of the rifle has long been a tradition of the United States military. Like the classic American television show Pimp My Ride, the U.S. Army knows soldiers love guns, so they attach a gun to your gun, dawg! Seriously though, attaching weaponry beneath a carbine can be a handy way to double the useable potential of your firearm. One such design was the U.S. Army’s M26 MASS or the M26 Shotgun.


Haven’t We Seen This Before?

Sure have. The Knight’s Masterkey famously utilized an underbarrel Remington 870 shotgun. This pump-action design was specifically built to give breachers a tool to rip down doors. It was made with Delta Force in mind but never saw major use.


The M26 MASS came to be in 2003 during the good ole Global War on Terror. A company called C-More systems designed the weapon. C-More might sound familiar, and that’s because they are famous for their open red-dot optics. Development began on the project in the 1990s as a successor to the Masterkey.

The Masterkey was a stop-gap solution, but the M26 MASS was a purpose-built design. The M26 MASS was a 12-gauge, bolt-action shotgun that fed from a three- or five-round detachable box magazine. Bolt action might inspire thoughts of precision sniper rifles, but alas, this was a straight-pull bolt.


The M26 MASS – A Bolt-Action Shotgun?

The straight pull bolt allows for quick cycling and makes it a more ergonomic option than a forward pump. The bolt sits behind the front-sight base and allows for rapid use compared to a forward-mounted pump. The bolt takes the form of a massive handle that’s easy to grip and rip.

Soldier fires gun
A soldier fires the M26 MASS. (U.S. Army)

A manual action offers some advantages over a semi-automatic shotgun. First, it’s simpler and lighter than a semi-auto gun. Second, semi-auto shotguns could not cycle less lethal or breaching loads. Soldiers could quickly cycle the gun when needed.

In its under-barrel form, the M26 MASS only weighs three pounds. That’s the same weight as an M203. The Masterkey weighs 5.7 pounds, so it was a significant reduction in weight and increase in practicality.


The M26 MASS could be removed from an under-barrel configuration and set up as a separate weapon with relative ease. As a stand-alone weapon, the M26 MASS was a super short shotgun with an M4 collapsing stock. If I was to use the M26 MASS for less lethal operations, I wouldn’t want it mounted to a rifle with lethal capabilities. It’s best to keep the two separated for safety reasons.



While reportedly the Army announced they would purchase 35,000 M26 MASS shotguns for service, it seems rare to see them in actual use. I can find plenty of pictures of these guns in use at Army ranges, but none overseas, or in the wild, if you will. Full fielding was supposed to begin in 2011.

If I had to guess, the M26 MASS shotgun simply wasn’t seen as that useful in our current wars. Shotguns are very niche weapons, and to be completely fair, the United States military doesn’t understand how to use the shotgun. There is very little institutional knowledge of shotguns and their advantages.

That likely puts the M26 MASS to the back of the armory. Plus, we’ve seen a big move away from under-barrel-mounted weapons. The Army and Marine Corps both moved away from the M203 and chose the M320 to use as a stand-alone grenade launcher. We like our rifles short and light, and adding a second weapon makes them quite hefty; plus, an under-barrel-mounted shotgun is still awkward.


The M26 MASS solved a lot of problems with the Masterkey but is still super awkward and slow. To use the weapon, you must assume a weird stance and grip. When breaching a door, you want speed, and using a weirdly unergonomic platform isn’t exactly the fastest solution to taking a door down. And shotgun-breaching is rare. If you can shoot a door off its hinges, you can likely put a rocket or breaching charge through it. That’s quicker and more likely to kill whomever is behind the door.


Can You Get an M26 MASS?

The actual M26 MASS is an NFA item that would be considered an AOW or short-barreled shotgun. The 7.5-inch barrel ensures you got to get ATF permission and pay a tax stamp. However, C-More also advertises a title 1 model with an 18-inch barrel known as the M26 CMC. The gun has an MSRP of $1,399, so be prepared to spend some money. Plus, it doesn’t seem like they are easy to find either.

However, with enough money, anything is possible. I’ve never handled or fired an M26 outside of a SHOT show booth, so let’s turn it over to the audience. Does anyone here have any experience behind an M26 care to share your thoughts? Let us know in the comments below!