Weasel_Master, I'm confident Rudy does to start with charge do the job, based on comments from customers and all his contribution on This web site, but I'm not cloning a Colt carbine or SMG, but somewhat wanting to build anything functional, that's close to them in seems to be, and https://landenbpajr.blogpixi.com/26857030/an-unbiased-view-of-colt-10-5-inch-9mm-smg-upper-receiver-assembly