Optimized for use with SAAMI-spec 7.62x51/.308 Winchester ammunition; NOT compatible with Armalite AR-10B, Noveske N6, Springfield Armory M1A, Rock River Arms LAR8, FN SCAR 17S, PTR-91, HK417 or any other rifles that utilize M14, FN FAL, or HK 91/G3 patterned magazines; Next-generation impact and crush resistant polymer construction; Constant-curve internal geometry for smooth feeding; Anti-tilt, self-lubricating follower for increased reliability; High-quality stainless steel spring, black-oxide coated (MIL-DTL-13924D); Anti-glare translucent MagLevel windows on both sides of the body along with a painted indicator on the spring allows for easy determination of rounds remaining from 1 to 25; Ribbed gripping surface and new aggressive front and rear texture for positive magazine handling; Paint pen dot matrix panels on the bottom of the body to allow for identification marking