The ALG Defense Ergonomic Modular Rail (EMR) was designed to be a cost effective, lightweight, ergonomic and modular option for the M4 Carbine and all mil-spec AR-15 variants. The ALG EMR was also designed to do a good job in meeting the ten design specifications for a good M4 weapon rail. Rail types include 10″, 12″ and 13″.

Instead of four sharp and jagged M1913 rails spaced at 90 degree intervals, the ALG EMR is fully ergonomic, maintaining its comfortable rounded shape throughout the length of the rail. The rounded top allows the shooter to easily wrap his or her thumb over the top of the EMR as many shooters like to do with a forward grip.

Accessory rails in the standard M1913 (Picatinny) configuration are provided with each ALG EMR so accessories can be mounted where the shooter desires. Accessory rails can be attached anywhere along the length of the rail in 45° intervals, including the standard 12, 3, 6 and 9 o’clock positions. The 12 o’clock rail will “co-witness” with the top of an M4 upper receiver for use with any front BUIS. The ALG EMR also includes 2 standard non-rotating QD slots on either side of the rail.

The weapon barrel is completely free floating when an ALG EMR is mounted. No force is put into the barrel from slings or bipods that could affect point of aim.

The ALG EMR is machined from a semi-billet extrusion made from aircraft grade aluminum. A semi billet extrusion is designed with extensive machining stock for 3D features that are machined directly into the rail so that the rail is one integral piece.

Current infantry doctrine makes extensive use of accessories that require attachment to a weapon rail. Flashlights, visible and infrared lasers, night vision and thermal sights all require a rigid weapon rail so that zero is not changed when a bipod or sling is used to support the weapon from the rail. The ALG EMR is a rigid interface for weapon accessories due to its precisely machined proprietary barrel nut and secure rail interface and clamping arrangement.

Use of aircraft grade aluminum and high strength steels in the ALG EMR give the entire assembly a good strength and performance to weight ratio.

Accessory rails are fastened to steel slide nuts and are fully captured in channels configured in the rail ID. Slide nuts are much more soldier proof than inserts as a cross threaded screw can easily be repaired with the replacement of a slide nut. It takes literally seconds to install or remove an accessory rail without standing on your head to deal with non-captured plate nuts.

The ALG EMR accessory rails are designed to securely attach to the rail with the supplied steel slide nuts. The slide nuts take the place of individual nuts which are difficult to tighten and maneuver inside the rail. By screwing the accessory rail screws directly into steel and not the aluminum rail, the attachment method is strong and vibration resistant.

Each ALG EMR comes with a precision machined, 2-1/4” long barrel nut that is machined from aircraft grade aluminum and hardcoat anodized for a durable surface. Also, included is the proprietary ALG EMR barrel nut wrench which is used to tighten the barrel nut to the upper receiver. The ALG EMR is required to be indexed to the gas tube, and includes all the necessary shim kits and instructions to do so. The rail is then slid onto the barrel nut and the precise barrel nut to rail fit precisely aligns the rail to the barrel. After indexing the rail to the receiver, six mounting bolts are tightened and the rail is secure.

Just by loosening six screws the ALG EMR can be slid off the barrel nut for cleaning or gas system maintenance. As quick as it is removed the ALG EMR is can be re-installed with the precise barrel nut to rail fit maintaining sight and accessory zero.

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