The 7.62x51 NATO PMAG 25 LR/SR GEN M3 Window is a lightweight magazine for SR25 rifles featuring constant-curve body and anti-tilt follower. Designed specifically for SAAMI-spec ammunition, the PMAG 25 LR/SR also features transparent MagLevel windows to allow rapid visual identification of approximate number of rounds remaining. *Note- compatible with Armalite AR-10A, Colt LE901-16S, CORE Rifle Systems CORE30, JP Enterprises LRP-07, KAC SR25, LaRue OBR, Les Baer .308, LMT .308 MWS, LWRCI REPR, Mega Arms MATEN, Noveske Gen III N6, POF P-308, Ruger SR-762, Ruger Precision Rifle, S&W M&P10, SIG716.