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Tactical Shotgun AR Stock Adapter from Mesa Tactical
Text & Photos by Jeff W. Zimba

If you regularly read the pages of Small Arms Review, one thing you know for certain is there is no shortage of innovation in the firearms industry. It seems as though there are new products, accessories and upgrades available on an almost daily basis. The old saying that, "you can't build a better mousetrap" doesn't apply to our industry at all. The Tactical Shotgun AR Stock Adapter from Mesa Tactical is just further proof.
Joining two completely different firearm platforms, Mesa Tactical of Costa Mesa, California has designed an adapter allowing the owner of a pump shotgun to utilize a collapsible AR-15 style stock and pistol grip. These adapters are currently available for the Remington Model 870, the Mossberg Model 500 and the Winchester Model 1300.
While the concept of a folding shotgun stock is not a new one, this particular design has a few features that make it quite unique. The stock adapters are investment cast and machined A356-T6 aluminum. They are hard anodized and have a very dark grey finish similar to many AR-15 type rifles.
Each stock adapter has 3 mounting areas, one on top and one on each side that will accept one of many available accessories including scope and accessory rails, sling swivels and shell holders. These mounting areas are designed to accept quick-release, push-button sling swivels, or the standard stud type sling swivels, whichever the operator prefers.
The threaded portions of these mounting areas utilize Heli-Coil steel thread inserts to ensure durability and a long life.
In the case of a military or law enforcement end-user, the collapsible stock adapter allows the shooter to utilize the same pistol grip and stock as on their issued AR-15 / M16 / M4 rifle system. This provides an immediate familiarity with the shotgun due to the training on the primary firearm and assists in a smooth transition from one weapon to the other. It also allows the owner to customize the shotgun with many different stocks and pistol grips that are already on the market.

Why use a collapsible stock?

The collapsible stock and pistol grip combination provide the shooter with several options not available on a standard length shotgun. For purposes of use in a confined space such as an automobile or doorway, the collapsible stock allows much easier movement and is far less restrictive. In cases where body armor is necessary or desirable, or even in cold climates where several layers of clothing are worn, the stock may be adjusted to correctly fit the shooter. This is also the case with a person who may be of small stature. There are several stocks on the market with 4 or 6 or even more possible positions allowing the shooter to have a shotgun that fits correctly in any situation. It also allows several shooters to have the ability to utilize the same gun, and fit each shooter correctly.
Unlike the shortened fixed-model stocks intended solely for use with body armor, this system allows the shooter to fully extend the stock for use when no body armor or heavy clothing is being utilized. In case the owner decides to have a more traditional feel or wants the extra stock length for a particular task, this adapter will also allow the use of a full length buffer tube to accommodate a standard A1 or A2 shoulder stock should it be desired.

Accessory Options

As mentioned earlier, each stock adapter has 3 mounting areas allowing the use of sling swivels, scope and accessory rails and shell carriers. Other accessories are also being designed at this time. The mounting areas are completely universal and will allow the use of any combination of accessories, including the "stacking" of sling swivels on top of other accessories. On the firearm tested for this article you will notice a shell carrier on the right side of the shotgun, and a long MIL-STD 1913 rail on the top. If the shooter wanted a rail on the top for mounting an optical sight but also desired a top mounted sling swivel for a particular carry technique, they would not have to choose one or the other. The design of the rail allows the sling swivel to be utilized in combination with it. Accessories currently available from Mesa Tactical for this system include a long rail for mounting on top of the receiver or on the left side of the receiver for use with many optics, standard flashlight and laser mounts, grips and several other products on the market today. A shorter mount for use on the right side of the shotgun, behind the ejection port, is also available.


The original stock is removed with a long flathead screwdriver (in most cases) and simply replaced with this adapter. After removal of the old stock is complete, the only additional tools necessary are a Phillips head screwdriver and an AR-15 stock wrench. Everything else comes with the kit. Once the adapter is secured to the shotgun receiver, the pistol grip and buffer tube are installed just like they are on an AR-15.


Shooting the shotgun fitted with the collapsible stock is not much different than the factory stock without a recoil pad. Though perhaps a little bit more abrasive, especially when used with slugs, the pistol grip transfers some of that recoil to the shooter's hand and arm so it is not all concentrated on the shoulder. The addition of a Pro Mag SJ088 recoil pad available from St. Johns Firearms ($10) helped to even further dampen the recoil. If you should order one of these, just make sure you specify if you have the 4-position stock or the 6-position stock, as they are not interchangeable. The extra recoil reduction attained with the pad, with length increase of less than 1/2-inch, is a wise investment.


The tactical significance of shotguns as entry and breeching tools as well as launching devices for several less lethal munitions and standard anti-personnel rounds, has been greatly enhanced with modern developments and accessories. While the addition of body armor and heavy clothing used to be a detractor, it no longer needs to be a concern when the stock can be quickly adjusted. Movement in close quarters can be achieved much easier without loosing the effectiveness of a full-length stock. The Mesa Tactical AR Stock Adapter is a tool that will make a positive addition to any arsenal, inventory or collection and give the end user much more flexibility than ever before. Retail price for the adapter and rail kit is $125. The retail price for the complete kit (includes adapter, M4 Stock, and rail kit) is $250. 4-round shell holders retail for $55.

This Just In

The unit tested by SAR is the "High Tube" stock adapter and must be used with a top rail and optical sight. Beginning in July there will be an option to purchase a "Low Tube" stock adapter allowing the shooter to utilize a traditional bead or other sight.

AR Stock Adapter
Mesa Tactical
1835 Whittier Ave, #A5
Costa Mesa, CA 92627
Phone: (949) 642-3337
Fax: (949) 642-3339

AR-15 Recoil Pads
St. Johns Firearms, Inc 1515 CR 210 West
Suite #103
Jacksonville, FL 32259
Phone: (904) 819-6644
Fax: (904) 824-6900


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