Mission: (5.56 NATO/.223 Remington) The PMAG 40 is a durable, lightweight, high reliability 40-round polymer magazine optimized for the AR15/M16/M4 platform and others. Description: The PMAG 40 features a four-way anti-tilt follower, constant-curve body, and pop-off dust cover that prevents dirt/debris intrusion and protects the feedlips during long-term storage. The PMAG utilizes a resilient stainless steel spring for corrosion resistance and a proprietary polymer to ensure durability and performance in all environments.