High-tube® Telescoping Stock Adapter and Rail Kit for Rem 870 (24 in rail, no clamp)

High-tube adapters have a comb height equivalent to an AR-15 and require an optics rail (included). High tube adapters allow proper cheek weld and eye alignment with popular optics such as an ACOG or Leupold CQT and others.

SKU: 90950



You save $70.00 (28%)!

System Concept and Product Overview

Use Mesa Tactical’s collapsible stock kits and adapters to install AR-15 adjustable buttstocks and pistol grips onto the venerable Remington 870 and Mossberg 500/590 shotgun platforms for the ultimate in tactical shotgun configuration performance.

The most important capability of these adapters is to facilitate the use of collapsing or telescoping stocks, which provide a shorter length of pull (LoP) than the factory stock, which is especially important for law enforcement or “tactical” operators. In addition, these stock adapters accept a hydraulic buffer from Crosshair™ that reduces felt recoil. The Mesa Tactical/Crosshair combination is by far the most robust and most effective of several recoil-reducing shotgun stock systems on the market.

There are two lines of Mesa Tactical telescoping stock adapters:

1. High-tube® telescoping stock adapters, that require the use of rail mounted optics;

2. LEO® telescoping stock adapters, which feature a stock elevation about an inch lower than the High-tube adapters and so don’t require sighting or aiming aids.

These adapters are available in two types of kits, adapter kits or complete stock kits.

Our High-tube adapters have a comb height equivalent to an AR-15 and require an optics rail (included). These specialized adapters are for certain law enforcement applications or competition. High tube adapters allow proper cheek weld and eye alignment with popular optics such as an ACOG or Leupold CQT and others. High-tube adapters and stock kits include nine inch or 24 inch top Picatinny optics rails. While the 9.50 inch rails can optionally be secured to the shotgun receiver as well as the stock adapter, the 24 inch rails are anchored at the front by a clamp. No gunsmithing is required to install. Minor fitting of fasteners may be necessary.

The concept is simple: the shotgun stock is replaced by an adapter that mimics the stock attachment point of an AR-15 lower receiver. This adapter accepts an AR-15 receiver buffer tube. The AR-15 collapsible stock and pistol grip can then be reliably attached to the shotgun. 

Stock kits additionally include an M4 Carbine style telescoping buttstock assembly, a Hogue rubber overmolded pistol grip, a stamped steel stock wrench and a push-button sling swivel. A slip-on rubber butt pad for the M4 Carbine buttstock is available separately.

Shotgun Platform Compatibility

The Telescoping stock adapter Shotgun Conversion Kits are available for the following 12 gauge shotgun platforms:

• Remington 870
Mossberg 500, 590

Some Mesa Tactical High-tube stock kits include an optics rail that mounts to the stock adapter and runs approximately 24 inches down the length of the shotgun, and is supported at the front by a barrel clamp or a magazine clamp, which is included with the kit.

Some kits for the Remington 870 do not include a clamp, as these are for customers who already have a Mesa Tactical barrel or magazine clamp installed on their shotgun. 

Mossberg rails use a magazine clamp that features either a short length of Picatinny accessory rail at the bottom, or a sling swivel stud. Note that adapter mount rails for the Mossberg 500 platform feature a “window” machined at the rear of the receiver to allow access to the tang safety lever.

Generally, Mesa Tactical telescoping stock adapters will not fit on semi-automatic shotguns. Most semi-automatic shotguns feature a return spring housing that extends from the rear of the shotgun receiver that makes it impossible to fit an AR-15 stock system to the weapon.

Stock and Grip Compatibility

Because the stock and grip interfaces of the Mesa Tactical High-tube telescoping stock adapter are almost identical to a real AR-15 rifle, this adapter can accept almost any stock or grip combination made for the AR-15. The only known limitation concerns duckbill style grips that, while they will still fit on the adapter, would probably need to have the duckbill filed off before use.

Recoil Buffer Kits

Mesa Tactical Recoil stock kits include a Crosshair™ recoil buffer assembly instead of the hollow receiver extension tube. The recoil buffer can absorb felt recoil. Install the recoil buffer according to the instructions below, just as if it was a receiver extension tube.

WARNING: The Crosshair buffer is spring loaded. Do not disassemble or serious personal injury or death could result.

WARNING: During firing the Crosshair buffer compresses up to ¾” as the shotgun moves rearward. DO NOT place eyes, hands or cheeks close to the grip of the stock adapter. Keep face and other body parts at least 2” from the threaded end of the Crosshair buffer.

Package Contents

The Mesa Tactical Telescoping Stock Adapter Shotgun Conversion Kit should include the following components:

  • 1 Cast aluminum and powdercoated telescoping stock adapter
  • 1 Receiver cap screw
  • 1 Receiver screw hex key
  • 1 AR grip screw
  • 1 Cast aluminum and powdercoated telescoping stock adapter
  • 1 Receiver cap screw
  • 1 Receiver screw hex key
  • 1 AR grip screw
  • 1 Picatinny scope rail
  • 2 Picatinny scope rail cap screws
  • 1 Picatinny scope rail cap screw hex key
  • 1 Machined nylon Picatinny scope rail rear spacer
  • 1 Molded nylon Picatinny scope rail forward spacer
  • 2 Aluminum mount point cover plates
  • 4 Mount point cover plate button-head screws
  • 1 Mount point cover plate screw hex key
  • 2 Threaded steel flush cups

Assembly of the Mesa Tactical Telescoping Stock Adapter Shotgun Conversion Kit requires no special tools and should take less than 30 minutes. All required hex keys and an AR-15 stock wrench are included with the stock kit. All you will need to provide is a Phillips head screwdriver (for the pistol grip), plus whatever tools are required to remove the old stock (an AR-15 stock wrench and stock nut is not included with the stock adapter kit, only with the complete stock kit).

Optionally, you might want blue Loctite® liquid thread locker for the screw threads. A torque wrench is also useful to ensure you are using the appropriate torque settings on the fasteners.

For assembly instructions (click here)


LEO stock adapters accept most third-party AR-15 stocks or pistol grips.

*The following items cannot be exported without a license

High-tube Telescoping Stock Conversion Kits.

Pocket Sling Attachments 

Adapter Mount SureShell Shotshell Carrier


All Mesa Tactical products are made in the USA of high quality materials and include LIFETIME WARRANTY.Mesa Tactical warrants that all products are free from defective material and  workmanship and, subject to the conditions set forth below, agrees to repair or  replace any part of a product that proves defective by reason of improper workmanship or materials without charge for parts and labor. In no event will Mesa Tactical be liable for damages, lost revenue, lost wages, lost savings or any other incidental or consequential damages arising from purchase, use or inability to use this product. No express or implied warranty is madefor Mesa Tactical product damaged by accidents, misuse, natural or personal disaster, or any unauthorized disassembly, repair or modification. Mesa Tactical’s warranty covers only repair or replacement of defective Mesa Tactical products. 

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