In-Box Review
US Army M4/M26 MASS
US Army M4 carbine with M26 Modular Accessory Shotgun System (MASS)
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by: Mario Matijasic [ MAKI ]


The M26 Modular Accessory Shotgun System (MASS) is a lightweight 12-gauge accessory shotgun system, originally developed for attaching underneath the barrel of the M4 and M16 MWS, just like the M203 grenade launcher. The system provides soldiers with a shotgun accessory module with lethal, less-than-lethal, and door-breaching capabilities. Previously, soldiers performing non-lethal and door-breaching missions would have carried 2 separate weapons, an individual combat weapon and a separate shotgun. This lightweight, multi-use shotgun attached to their primary weapon system would provide soldiers with the capability to breach doors quickly and efficiently without requiring them to carry an additional weapon.

The original M26 MASS idea has been based on the Knight's Armament Company's Masterkey system, dated back to 1980s,which originally included the shortened Remington 870 shotgun mounted under the M16 rifle or M4 carbine. The M26 are manufactured by the C-More Systems and improved upon the Masterkey concept with a detachable magazine option and more comfortable handling, thanks to the bolt-operated system. At the present time small numbers of M26 MASS shotguns are issued to US troops in Afghanistan, and, according to available sources, these weapons are well received by troops who used them.


Live Resin is an aftermarket company from Russia, specialized in producing high quality weapon and accessory sets. This review covers their US Army M4 carbine with M26 Modular Accessory Shotgun System (MASS) (LRE-35102) set.

The set is packed in a zip-lock bag safely secured between a firm cardboard backing. The box art on the front shows all the kit parts, while the one on the back lists Live Resin offerings which could be combined with the basic M4 kit: US Army scope sets (LRE-35007, LRE-35008 and LRE-35028), Insight's Technology AN/PEQ-2, AN/PEQ-15 (LRE-35010), Forward grip set (LRE-35011) and Harris bipod set/Surefire tactical Weapon Lights set (LRE-35012).

The kit consists of 14 parts: 6 M4/M26 and 8 M4 ammunition magazines. The grey resin looks really good, however this is the first time I found a slight defect in Live Resin weapon sets. All the M26 MASS magazines feature tiny vertical lines… I’m not sure if it is a leftover from the 3D prototyping procedure or a casting flaw, and although not very pronounced these need to be sanded carefully. All the other details are perfectly rendered though.

The M4s depicted in this set are fitted with integral Picatinny-type accessory rail on the upper receiver and Knight's Armament Company (KAC) Rail Interface System (RIS) handguard. The upper receiver rail provides the attachment point for scopes, while RIS handguard could be fitted with various laser designators, forward grips, tactical lights or bipods. All the accessories are available separately from Live Resin. These M4s are mounted with M26 Modular Accessory Shotgun System (MASS). The M26 MASS is attached to the carbine using mounting brackets at the front sight and handguard’s slip ring assemblies. The front section of the weapon features the feed, ejection port and folding charging handle. The charging handle is set to the left side of the body, the soldier must grasp the handle and pull it back to introduce a new shell into the firing chamber and eject spent casing. The barrel is purposely short for close-quarters work, and is capped by a large, slotted compensator fitted over the muzzle.

Although very similar and equipped with underbarrel M26 MASS, all the weapons in this set are not identical; there are 4 slightly different M4/M26 variants included, which are designated LRE-35102A to LRE-35102D. The differences include: two different buttstock versions, retracted or fully extended buttstock, handguard panel on the upper RIS handguard present or not, and back-up iron sight (BUIS) present or not. Moreover, the M26 in this set feature either 3 or 5 round detachable magazines, as well as 3-inch standoff device extended or retracted. The standoff device is used during the door breaching procedures; without such a standoff device at the muzzle, the risk of damaging the barrel while pressing it into the door greatly increases.

These weapons are cast without their ammo magazines. Instead, 8 different magazines are included in the set as separate pieces which can be fitted into a tiny opening in the M4 lower receiver assembly. The selection includes: 30-round M4 magazine (2x), with Ranger Plate USGI (1x), with 5.56 NATO 3-pack accessories attached (1x), 30-round Magpul PMAG (1x), with Ranger Plate USGI attached (1x). The set also includes coupled 30-round M4 magazines (1x) and two magazines which can be coupled by the modeler himself. The magazines are easy to remove from their carrier block and fit perfectly to the M4.

Impressive! That’s the first word that comes to mind after taking a good look at these 1/35 scale masterpieces. All the M26 MASS features are clearly identifiable and well rendered in this kit. The level of details is absolutely amazing… the folding charging handle, the standoff device at the muzzle, and overall the complex shape of the weapon are modeled to perfection. Live Resin uses state-of-the-art 3D prototyping with the 5 micron resolution, and it definitely shows. With some accessories from Live Resin range these weapons will really come to life.


This kit features US Army M4 carbine with M26 Modular Accessory Shotgun System (MASS). The kit includes 6 M4/M26 MASS in slightly different configurations. The resin cast is very good with extremely well defined details. As with many other Live Resin weapon offerings, these weapons should be upgraded with accessories (optical sights, laser designators, forward grips, etc.) available separately from Live Resin.

Thanks to Yaroslav from Live Resin for this review sample.


C-More Systems
Global Security
Military Factory
World Guns
PEO Soldier
Highs: Cast well and full of intricate details, these weapons are a work of art. Designed using CAD and 3D prototyping, these weapons are actually miniature copies of the real M4/M26 MASS system.
Lows: Tiny 3D printing lines on the MASS magazines.
Verdict: Highly recommended.
Percentage Rating
  Scale: 1:35
  Mfg. ID: LRE-35102
  Related Link: Live Resin website
  PUBLISHED: Sep 20, 2013
  NATIONALITY: United States

Our Thanks to Live Resin!
This item was provided by them for the purpose of having it reviewed on this KitMaker Network site. If you would like your kit, book, or product reviewed, please contact us.

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About Mario Matijasic (Maki)

You wonder how did this addiction start? I was a kid when my dad broght home a 1/72 Concord airplane; we built it together as well as couple of other airplanes after that. This phase was just pure fun: glue, paint, decals in no particular order... everything was finished in a day or two. Then I disc...

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