The mdp-9 features a patent pending roller-delayed action which significantly reduces the weight and recoil of the gun.Making it one of the softest shooting pistol caliber carbines on the market.And at just 14 long and 3.6 lbs., its small enough to be carried comfortably on a sling or in a backpack.It also runs on glock 9mm double stack magazines, has last round bolt hold open and an extended mag release.All of which makes magazine changes much faster than conventional subguns.Action: Semi-AutoCaliber: 9mm LugerBarrel Length: 5.85"Grips: Black PolymerWeight: 3.60 lbsOal: 14"Barrel Length Range: 5" to 5.99"Weight Range: 3 lbs to 3.99 lbs