Detailed video on how I built my AR15 upper receiver. Building an AR15 with a Timney Trigger is super easy. You only need a few tools and you're all set. Anyone and I mean anyone can build one. Don't let anyone tell you you need some shop to assemble it for you...you can do it! I mentioned in the video to use a 3/16" drill bit...use a 1/8" drill bit to check barrel nut and gas tube inlet alignment.