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M26 (MASS)

Modular Accessory Shotgun System [ 2003 ]

The M26 MASS is currently under active assessment with elements of the American military.

Authored By: Staff Writer | Last Edited: 05/20/2020 | Content ©www.MilitaryFactory.com | The following text is exclusive to this site.

Recent American combat actions in Iraq have once again brought a focus concerning the warfighter in an urban environment. The warfighter requires weapons that are utterly reliable in close-quarters and can neutralize threats without hesitation or allow access to otherwise restricted areas of the battlefield. For over a century, the American soldier has utilized the shotgun for this charge and the World Wars as well as the lesser conflicts of the 21st Century unveiled a slew of developments in that regard - all based on a principle established at the end of the previous century. For the modern warfighter of the new millennium, this has now come to fruition in the form of the experimental "M26 Modular Accessory Shotgun System" (MASS). Design of the M26 is attributed to engineer Ira Kay and development occurred at the beginning of this century. Active trials involving the weapon system was under way in 2003 under the developmental designation of "XM-26". Serial production then began in 2011 under the C-More Systems brand label.

The M26 is unique in its design as it can be fielded as a standalone weapon system or as an accessory part of the M16 Assault Rifle and M4 Carbine series of automatic weapons. In the former mode, the weapon is equipped with a full telescoping stock and receiver with integral pistol grip and optional optics. In the latter mode, these are removed and the system is fitted under the handguard of the host weapon to double the tactical value of the warfighter (this doubling known as "force multiplier"). Earlier programs attempted such a mating of primary weapon and secondary accessory - the most notable perhaps being the Knight's Armament "KAC MasterKey" of the 1980s involving a shortened Remington M870 pump-action slide shotgun fitted under the barrel of an M16 Assault Rifle.

As a standalone shotgun system, the M26 sports a stock at the rear of its receiver. The pistol grip is ergonomically shaped and angled rearwards in the usual way. The trigger is surrounded in a large, oblong ring which allows for a gloved hand to be used. Over the receiver can be fitted a basic sighting device for accurized short-ranged fire, mounted across the provided MIL-STD-1913 accessories rail span. The frontal section of the weapon remains wholly intact from its accessory counterpart and features the feed, ejection port and charging handle. The charging handle is set to the left side of the body and is manually-actuated as a "straight-pull", bolt-action system similar to that of a bolt-action rifle. Therefore, the user manages the handle to introduce a fresh shell into the firing chamber and eject any spent casings found in the chamber prior. The barrel is purposely short for close-quarters work which lends itself well as an under-weapon accessory. The barrel is further capped by a large, slotted compensator fitted over the muzzle. Sling loops are found ahead of the receiver and at the telescoping shoulder stock at the rear. The magazine is a squat, detachable box design that comes in two forms - a 3-shell version and a 5-shell version while being chambered for the 12-gauge shell. Overall length of the full shotgun form is 19.7 inches with the stock fully extended (13.8 inches otherwise) with an overall weight of just over 4lb.

As an under-weapon accessory system, the M26 retains the portion of its receiver housing the internal working components as well as the magazine feed, ejection port, charging handle and barrel. The accessory connects to the M16/M4 via a single pin that can be simply (and quickly) managed with the point of a cartridge or similar instrument/tool, allowing the operator to remove the accessory as speed if need be. Because the accessory lacks the pistol grip of the standalone version, the magazine of the M16/M4 doubles as the pistol grip for the M26 accessory (as it does with the underslung 40mm M203 grenade launcher). All firing and reloading functions of the M26 remain the same as in the standalone version and sighting is now accomplished through the host weapon's sighting device (if equipped). The warfighter is now given a lethal secondary option when clearing structures of enemy personnel at extremely close range, an option beyond that of his standard-issue weapon. The 12-gauge firepower of the M26 can also be used to "unlock" doors with relative ease. Overall weight of the M26, as an accessory, is just 3lbs.

As a combat shotgun development, the M26 is cleared to fire the basic anti-personnel/anti-material slug. Buckshot can also be used as an anti-personnel spread solution. The M26 can also fire riot control ammunition in the form of rubber slugs, pellets or tear gas canisters as required (these collectively recognized as "non-lethal" rounds due to their intended non-lethal purpose).

Due to the success of the M26 modular system in active combat operations, the series is now poised to replace the long-running and outgoing Mossberg M500 full-length, pump-action slide combat shotguns currently in service with the US Army (since 1961). In the old ways of waging war, an operator went into battle with one weapon or the other. The M26 development now allows the warfighter to go into battle with two weapons for the weight gain of one. While production is low-rate at the moment (2013), the US Army is committed to procuring the M26 system in quantity.©MilitaryFactory.com
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Service Year

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United States


Modular Accessory Shotgun System

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(OPERATORS list includes past, present, and future operators when applicable)
Close Support
Extreme close quarters use; trench-clearing; doorbuster; security.
Special Purpose
Special purpose weapon for a specially defined battlefield role.

Overall Length
500 mm
19.69 in
Barrel Length
180 mm
7.09 in
Empty Wgt
3.31 lb
1.50 kg

None as Standard; Optional Optics.


Manually-Actuated Bolt-Action

Manually-actuated process of managing the bolt lever to eject spent cartridge case, clearing the breech, to introduce fresh catridge into the chamber.
(Material presented above is for historical and entertainment value and should not be construed as usable for hardware restoration, maintenance, or general operation - always consult official manufacturer sources for such information)



Sample Visuals**

Graphical image of a 12-gauge shotgun shell
Rounds / Feed

3- or 5-round detachable box magazine
Cartridge relative size chart
*May not represent an exhuastive list; calibers are model-specific dependent, always consult official manufacturer sources.
**Graphics not to actual size; not all cartridges may be represented visually; graphics intended for general reference only.
M26 MASS - Base Series Designation

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Images Gallery

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Image of the M26 (MASS)
Image from official marketing material.
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Image of the M26 (MASS)
Image from official marketing material.


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