The M26 Modular Accessory Shotgun System is a straight pull bolt action shotgun that can be used standalone or fitted to an M16 or M4. It is designed to fire lethal, non-lethal and breaching rounds.

Military.com were not fond of the action when they recently tried it:

That’s all well and good, but I found the cocking mechanism to be clunky and inefficient. Instead of an under-barrel pump-gun style action, a metal bar attached to the bolt extends out to the side, forcing the shooter to transition his hand position to load another round into the breach … I wasn’t the only one with that complaint.

38,000 MASS’s are going to be fielded in late 2008 to replace the Mossberg 12 gauge pump action shotguns.

Specs of the XM26, the M26 may have changed slightly:

* Caliber: 12 gauge
* Operation: Straight pull bolt-action.
* Capacity: 5 round detachable magazine.
* Ammunition: 2.75 and 3 in lethal, less-lethal and breaching rounds.
* Barrel length: 7.75 in (197 mm) with integral breaching stand-off adapter.
* Under-barrel version:
* Overall length: 16.5 in (419 mm)
* Weight: 2 lb 11 oz (1.22 kg)
* Stand-alone version:
* Overall length: 24 in (610 mm) (stock collapsed)
* Weight: 4 lb 3 oz (3.80 kg)
The standalone configuration:

Some more photos. Click to increase the size of each photo.