SWEDISH K M45 semi auto tube blank. This tube has a reduced inner diameter and an outer diameter matching an original. Designed around our Swedish K semi auto kit (M45-SAK) and cannot accept an original bolt. The tube WILL require machining on a lathe to print (included), applying the template (included) with glue (not included), and then cutting out the slots and ports. This is a NON-RETURNABLE item and COPYRIGHTED for single use only, all sales final.