- Type: Flat-Top
- Series/Collection: Minimalist-SQ
- Handguard: Free-Floating Rifle-Length SquareDrop
- Caliber: 300 AAC Blackout
- Barrel Type: Lightweight
- Barrel Length: 16"
- Barrel Material: FNC Treated 4150
- Muzzle Type: 51T Rachet Mount Flash Hider
- Receiver Type: Integral Brass Deflector
- Receiver Finish: Hardcoat Anodized Black
The Bushmaster XM-15 Minimalist-SD is built on the versatile Bushmaster modular MSR upper platform. The barreled upper receivers can be used on existing MSR-type lower receivers, all receivers feature integral brass deflectors . The 4150 chome-moly-vanadiem steel barrels feature hard-chrome lining in both bore and chamber for extended barrel life.The XM-15 300BO features a free-floated handguard, a 16" FNC treated 4150 lightweight barrel and a lightweight gas block.