FORWARD CONTROLS DESIGN
LMC Low Profile Magazine Catch
The LMC (Low profile, duty Magazine Catch) is a non-ambidextrous magazine catch for the AR-15 and M16, built around one goal: making an accidental magazine drop harder. Billet machined in 4140, heat treated, and black nitride coated.
It came out of the development work on the EMR-A, which uses the same two ideas.
How It Prevents Drops
The catch is 0.01 inches longer than TDP spec, 0.06 against 0.05, where it engages the magazine's catch cutout. A magazine drops once the catch travels past that engagement, so a longer ramp means more travel is required before anything releases.
Why not 0.07 or 0.09? Balance. Push it further and you start stacking tolerances against aftermarket magazines. 0.01 does the job without introducing a new problem.
The shaft is shorter by one full turn of the magazine catch. With a TDP spec button correctly installed at eight revolutions, the top of the button sits slightly below the receiver's magazine release fence rather than flush with it. A button below the fence is harder to bump against a plate carrier, a vehicle seat, or a barricade.
Winterized
In freezing weather, a TDP spec magazine catch lets water pool and freeze inside the cavity formed by the catch plate against the lower receiver. The LMC's plate is thicker, sitting below the receiver but protruding slightly, which reduces the space available for water to collect.
Pooling patterns vary, so this is reduction rather than elimination.
The 10.9 in-lb Spring
The LMC ships with a 10.9 in-lb magazine catch spring installed. FCD had these custom made in 2017 for the EMR-A, where a stiffer spring offsets the mechanical advantage of the ambi lever.
On a non-ambi setup it simply makes the right side button harder to press, which is the point.
Before You Order
Do not use the LMC on large frame or .308 ARs. The shorter shaft is sized for AR-15 and M16 width receivers, .308 mag catch shafts are longer, the winterizing works inconsistently on large frame lowers, and the lengthened catch does not apply.
Incompatible with the Griffin Armament Mk2 and POF ambi lowers, or any receiver using an ambidextrous mag catch with a short rod actuating a TDP spec catch.
The LMC is designed to work with through hole TDP spec magazine release buttons. FCD does not recommend blind hole buttons or tall extended magazine releases on defense and duty 5.56 rifles. The EMR-H is the right pairing here; the EMR-HC is for .308 lowers and protrudes 0.08 inches over the fence on a 5.56 receiver.
What's Included
1x FCD LMC Magazine Catch with a 10.9 in-lb spring installed
Specifications
- Billet machined 4140, heat treated, black nitride coated
- One piece milled construction
- Non-ambidextrous magazine catch
- Catch length 0.06 inches against TDP spec 0.05
- Shaft shortened by one full turn for lower button height
- Winterized against water pooling
- Ships with a 10.9 in-lb magazine catch spring
- For TDP spec AR-15 and M16 lower receivers
- Not for AR-10, .308, or large frame ARs
- Not compatible with Griffin Armament Mk2 or POF ambi lowers
- Made in USA
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