The normal SMG uses a ten.5 inch barrel With all the common “chook cage” flash suppressor and frequent carbine handguards. The barrel incorporates a chrome lined bore and chamber. The barrel can also be manufactured in sixteen-inch length with the business/LE carbines. The best part is, you can use 9mm https://coltsmgupper20639.thezenweb.com/colt-smg-upper-an-overview-64403942