EMR-A is a long in development ambidextrous magazine release for .223 and .308 AR receivers. The original concept and design were complete in 2015. After numerous changes to the mag catch geometry and lever shapes, the final design was made into working prototypes in 2017, and first shown in public at Cola Warrior West III.EMR-A is an ergonomic ambidextrous magazine release. The placement of its lever is well thought out to closely mirror the magazine release button on the right side. The portion immediately below the bolt catch’s lower paddle has a lower profile to avoid interference, heretofore a common drawback of popular ambidextrous mag catches, it is also left smooth. The serrated length of the lever is split into shallow V-shaped serrations (80%) that conform to the curvature of the user’s finger, and straight serrations (20%) that form a natural index point and provide additional traction. FCD refers to the design as a Multi-faceted Control Surface, the difference MCS makes has to be felt to be fully appreciated.
A 10.9lb rated magazine catch spring is included with each EMR-A. FCD has long considered the standard magazine catch spring to be rather weak (rated at 8.3lb), accidental/unintended mag drops can take place if a user slings his weapon, and has gear and pouches on the vest. A stiffer mag catch spring mitigates these risks, thus it is an integral part of the EMR-A package.
EMR-A’s catch is made from CNC machined 4140 steel and black nitride coated, its lever is 7075 aluminum and Type 3 hard coat anodized. The roll pin has a shear strength of 800lbs.
Standard for EMR-A, Nov. 2019 and Onward:
The LP (low profile) mag catch shaft option reduces the mag catch shaft length by a full revolution, or 0.03. The LP option on the EMR-A (not available for serrated lever EMR-A till mid-2020) reduces the installed height of the right-hand mag release button, resulting in a right-side mag release button that sits below the mag release fence. This is FCD’s latest step to mitigate accidental/unintended mag drop risks.
The LP on the EMR-A will not reduce the EMR-C’s installed height on an AR15/M16 to the point where EMR-C doesn’t constitute accidental/unintended mag drop risks. The LP option’s shorter mag catch shaft aims to reduce the installed height of a TDP spec mag release button (such as FCD’s EMR), it isn’t a solution for extended mag releases, the installed height of which would require a drastically shorter shaft to offset. EMR-C is meant for 7.62mm ARs, even though it works on an AR15 / M16, FCD suggests it be relegated to 7.62mm ARs and gaming ARs, not for defense and duty.
- EMR-A’s lever pivots on the receiver.
- EMR-A needs to be removed before installing/removing the trigger. EMR-A is installed and removed in the same manner as a factory mag catch.
- Please wear eye protection while installing EMR, EMR-C, and EMR-A with the 10.9lb mag catch spring, there’s considerable spring tension in the 10.9lb spring.
- For 308 ARs, or thicker non-5.56mm spec lower receivers, you will need an EMR-C to offset the AR15/M16 spec mag catch shaft.
- Due to the lack of standards for 308 ARs, EMR-A may not work with all 308 AR style lowers.
- Geissele’s Maritime Bolt Catch. Material from either the top edge of EMR-A’s lever or the bottom edge of Maritime Bolt Catch’s lower paddle may need to be removed for both to work together. The close proximity of these two control surfaces makes this combination less than ideal.
- CMC’s anti walk pins
- KNS Gen 2 anti-rotation trigger/hammer pins. KNS Gen2 Mod2 and Gen JJ, and Gen ST (Spikes Tactical) are compatible with EMR-A with a standard lever, but not with an extended lever. Gen2 Mod2’s pins connecting bar may require minor fitting on thicker receivers to create adequate clearance for the EMR-A’s lever when pressed.
- HK 7.62mm AR-style rifles, MR762 series.
- Aero 308 AR lower receivers.
- Hodge Defense Mod 2 lower receivers.
- Battery assist device levers.
- Receivers with the left side fence around the bolt catch and mag catch, such as some CMT, Magpul, and AR15.com billet receivers. EMR-A requires the left side of the receiver to more or less adhere to TDP specs.
Due to the lack of standards for 308 ARs, with every manufacture specs differing from another, FCD does not recommend EMR-A for 308 ARs.