I must say that this was the most fun/entertaining and informative thing I've done in a long time. I got my 80% lower a couple about a year and a half ago. A few weeks later, I bought a jig, then a few weeks ago, my friend and I got a Chinese milling vise for a drill press. I had lost the instructions and blueprints, so I got what I needed off the utube and bushmaster's site gave me a blueprint.
The jig was easy to use and looking back, I wish I'd scribed the top of the FCG with and awl and removed the top of the jig. We used a 3/8" and 1/2" end mill to mill out the FCG pocket. Before any machining, we drilled the holes for the pins and safety. There was a bit of clean-up work to be done with a dremel, but that was easy and fun. You can get a jig in which you use a small drill bit, then a larger one, but we mostly milled this
thing out.
A generic parts kit was fitted and now all I need to have a functioning lower is a buffer assembly and a stock.
I know I could get a complete lower for less than $150, but I'd still not know about fitting, and assembly. I highly recommend this.
The jig was easy to use and looking back, I wish I'd scribed the top of the FCG with and awl and removed the top of the jig. We used a 3/8" and 1/2" end mill to mill out the FCG pocket. Before any machining, we drilled the holes for the pins and safety. There was a bit of clean-up work to be done with a dremel, but that was easy and fun. You can get a jig in which you use a small drill bit, then a larger one, but we mostly milled this
thing out.
A generic parts kit was fitted and now all I need to have a functioning lower is a buffer assembly and a stock.
I know I could get a complete lower for less than $150, but I'd still not know about fitting, and assembly. I highly recommend this.
