HM Defense HMB Enhanced Bolt and Cam Pin for AR-15
Enhanced Durability AR-15 Bolt
The HMB bolt has a very specific mission: to prevent your AR-15 bolt from snapping in half around the cam pin. This is the most common failure point for bolts, since the amount of material surrounding the cam pin is very thin. The HMB design simply shortens the cam pin, and builds up material in the bolt, providing more mass to endure high pressure and hard usage.
The HMB bolt comes complete and ready to drop into a standard AR-15 bolt carrier group. It already has gas rings, ejector, and extractor already installed. You can re-use an existing, standard firing pin for installation.
- Caliber: 5.56 NATO, .300 BLK, .350 Legend
- Bolt Material: 9310 Steel
- Cam Pin Material: 4340 Hardened Steel
- Finish: Black Nitride
- Includes Bolt, Cam Pin, and Gas Rings