The Black Rain Ordnance SPEC15 Complete Upper delivers precision performance in .458 SOCOM caliber with a 16" 4150 chromoly barrel and premium American-made components.Black Rain Ordnance SPEC15 Complete Upper Receiver.458 SOCOM caliber with 1:14 twist rate16" 4150 chromoly barrel for durabilityExpanded ejection port for reliable cycling15" M-LOK hybrid handguard systemComplete bolt carrier group with .458 boltCharging handle with oversized tactical latchBRO .458 muzzle brake includedIncludes one metal magazine optimized for .458 SOCOMPerfect for hunters and enthusiasts seeking the power of .458 SOCOM in a complete ready-to-install upper receiver assembly crafted with American precision and quality.