Stern Defense MOD4 Complete Upper Features The Stern Defense MOD4 Complete Upper is engineered around a 4 barrel in 9mm with a 1:10 twist rate giving shooters a short fast handling platform built for close quarters use. The barrel is machined from chrome moly steel and finished in Melonite a nitride treatment that improves wear resistance and keeps the bore running smoothly through repeated cycles. Threaded for muzzle devices the barrel accepts compensators and the SD MBC 9mm blast can to help tame recoil and muzzle rise. This combination of twist rate barrel treatment and threading gives builders a dependable ready to run 9mm upper for their pistol caliber carbine project. The upper receiver itself is machined from aluminum and anodized for durability standing up to the wear of regular range use and field carry. It comes complete with a bolt a charging handle and a 4 MOD 4 M-LOK handguard so the only thing left to add is a compatible lower. The Glock pattern cut lets it mate directly to Glock cut lowers or to Stern Defense adapters giving builders flexibility in how they configure their pistol caliber carbine. Laser engraved and made in the U.S.A. the Stern Defense MOD4 upper is a compact well finished option for anyone assembling a 9mm PCC. Stern Defense MOD4 Complete Upper Specifications Manufacturer: Stern Defense Model: MOD4 Complete Upper Caliber: 9mm Barrel Length: 4 Barrel Material: Chrome Moly Steel Barrel Finish: Melonite Twist Rate: 1:10 Material: Aluminum Finish: Anodized Handguard: 4 MOD 4 M-LOK Includes: Bolt Charging Handle Receiver Compatibility: Glock Cut Lowers or Stern Adapters Country of Origin: Made in USA Available At: GrabAGun