Stern Defense BU9 9mm AR15 Bolt MagPhosphate Finish Glock Colt Compatible

The Stern Defense BU9 9mm bolt for AR-15 platforms delivers a purpose-built solution for integrating 9mm Luger operation into your rifle setup with a Mag-Phosphate finish that resists wear and corrosion. Engineered to fit AR-15 compatibility and designed to work seamlessly with common Glock and Colt-style components, this bolt combines reliability with practical versatility for 9mm conversions and multi-caliber builds. The bolt is sized and profiled to maintain proper timing and lockup within ty