SIG SAUER Bolt Assy, Tapered Lug, .300, Rattler O Ring, KIT-RATTLER-BOLT

300 Rattler O-ring 300BL. Sig Sauer machined these Bolt Carrier Groups from steel and coated them with a hard-anodized coating to ensure they're as rugged as the legendary weapons they were designed for. For even tighter lock-up the Sig Sauer .300 Bolt Assembly uses a tapered lug bolt design.