If you live in a state with restrictive hunting laws and need to use a straight wall cartridge, the Dirty Bird 16 GUNNER Carbine 350 Legend M-LOK Upper Assembly is the perfect solution. We wanted to make a durable, lightweight, and affordable upper for one of the most exciting calibers right now, 350 Legend. All of this was predicated on the right choice of barrel, which is why we went with the very popular Faxon Firearms 16 GUNNER 350 Legend Carbine 4150 Nitride Barrel.Faxon Firearms 16 GUNNER 350 Legend Carbine 4150 Nitride Barrel Barrel Material: 4150 CMV Barrel Type: Button Rifled Barrel Caliber: 350 Legend SAAMI Barrel Twist: 1:16 Barrel Length: 16" Barrel Profile: Gunner Barrel Gas System: CarbineWe added one of the nicest A2 Flash hiders that you could find for a 9mm Carbine to reduce muzzle flash.The upper is then built on a top-tier 7075 forged upper receiver, and fitted with a Dirty Bird SMRS V2 Handguard. Key features of this handguard include: Patented ASAL (Anti-Slip, Anti-Lift) mounting system Included M-LOK QD Mount "Competition Cut" top railThis upper ships with an MOA Guarantee and is covered by the Dirty Bird Limited Lifetime Warranty.