This is a Lancer Magazine known as the L7 Advanced Warfighter chambered in 308 Winchester, model L7-10-SMK.
The L7AWM is a lightweight magazine with an integrated front guard and welded steel feed lip which provides maximum stiffness and reliability while preventing dimpling to the front of the magazine. A switchable drain in the floor plate lock comes standard on all L7s" allowing users to configure the magazine for either water-borne or extreme dust conditions. The L7AWM is designed to work in multiple weapon systems - SR25" DPMS 308" SIG 716" LM308" etc.
Features:
Stainless Steel Spring
Aggressive Texturing
Stainless Front Guard
Switchable Drain on Bottom
Stainless Rear Feed Lip