M4 barrel shortening and stock shortening in Benelli Posted June 18, 2014 Hi, I am a gunsmith, soon to be Class 2 manufacturer, I have cut down several M4 barrels to the factory 14" Entry Model. I face and chamfer the OD, shim the front sight and mag tube and lightly spot TIG weld them in proper location. This is stronger than silver soldering and if done properly, uses minimal heat. I then open choke to IC for proper patterning. I charge $250 plus shipping. I can also shorten the factory stock length. After I cut to your desired length, I make a custom, removable aluminum adapter for mounting a Sims Recoil Pad, properly fitted to your gun. Cost is $150 plus shipping. Understand you must have your approved ATF Form 1 back before you can mount this on the reriever or even have the barrel and receiver in the same location. I will soon be able to do entire SBS conversion, including ATF paperwork and engraving for direct return to you (if in Maine) or your local Class 3 dealer in your state.