The Griffin ECS Stock represents the optimized general-purpose stock for the M4 carbine. After development, in testing of actual units from the first production run, we drop tested an M4 carbine mounting the ECS stock in one-foot increments from 1 foot to 10 feet onto concrete without failure*. As a comparison a single drop of an issued M4 carbine stock from 5 feet resulted in a sheared mil-spec locking pin and stock locked on the receiver extension due to binding of one of the broken pieces of the pin.
The ECS confronts design deficiencies in legacy systems. The current issued locking latch pin will bend and shear at the reduced diameter threaded shank, promoting stock failure- Griffin replaced it with a full diameter hardened stainless tool steel pin. The music wire spring is not a material recommended for outdoor use- the Griffin ECS uses 17-7 stainless steel springs which are outdoor use rated. The Griffin ECS also has water and debris evacuation ports compatible with the Griffin Maritime Receiver Extension, increasing system reliability and durability in extreme conditions. An anatomically angled, 60 durometer A Shore rubber pad promotes straight line recoil, reducing muzzle climb associated with 90-degree angled systems. The rubber pad further provides non-slip shouldering and comfortable recoil dampening, in weather conditions to -40F. An Ambidextrous, anti-rotation QD sling point is integrated into the stock, eliminating the capacity of the sling to wrap up when the firearm is stored or handled un-slung. Manufactured from high strength materials, the Griffin ECS stock is a compact, fully featured, no-compromise stock you can count on.
It is important to be aware of the flaws in mil-spec receiver extension geometry- mortaring a rifle to clear a malfunction may possibly damage a receiver extension. The most durable position for mortaring a carbine is with the stock fully collapsed. This reduces risk of damage to the receiver extension and stock to a minimum. Using a 7075-T6 receiver extension is critical for durability in rough handling.
Drop tests were performed with stocks in the closed position. Durability of AR type stocks are limited by the design of the mil-spec receiver extension geometry. Fully collapsing the stock maximizes the durability of the assembly. Griffin will be offering an MRE-HD receiver extension that will provide this level of durable performance regardless of position.