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Bolt Carrier Group

Don’t Buy a Nitride Bolt

Nitride looks good on paper, but AR bolts are a poor place to use a high-temperature ferritic nitrocarburizing process. This article explains how nitriding can over-temper the bolt after heat treatment, reducing core strength and fatigue life in the area that matters most: the cam pin hole and bolt lugs.

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Don’t Buy an S7 Bolt

S7 is tough, but it is the wrong kind of tough for an AR bolt. This article explains why through-hardened tool steel lacks the hard case, ductile core, and surface fatigue resistance that case-hardened Carpenter 158 and 9310 bolts rely on for long-term cyclic durability.

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