I've been wanting to make an RVA for my AR2078 for some time now, but not having a metal lathe or milling machine, I was a little hesitant about how to go about it using only a cheap Mastercraft drill press, Dremel, etc... I'm sure (?) I could have whittled something out - maybe - but I AM sure it would have been fairly crude with brutal tolerances!

So I contacted none other than our very own SeanMP to see if he could possibly make me one, or at least give me some pointers on how to attack the project using my "caveman" tools. Man...am I ever glad I did! I was told to bring all my factory pieces down and he would whip one up for me on the spot...

Here is the finished product with the factory one above for comparison:
m_AR RVA 001.jpg

I went with this style as I wanted both an RVA, but still have the gun retain its factory look. The new cocking block is .200" longer than stock to allow a bit more adjustment range, and now sits right tight to the new end cap. Right behind the cocking pin a hole was drilled/tapped 8-32, where a nylon plug, the smallest spring I've ever seen, and an 8-32 set screw make up a "brake" to keep adjuster/spring guide from moving once set where I want it. The threaded end of spring guide was also drilled/tapped 8-32 for a set screw (with red Loctite applied), and spring tension is adjusted by inserting an allen key through a small hole drilled in end cap.

Seeing as the end cap now sits tight to cocking block, it was bored .312" x .450" deep to allow adjuster enough room to be back off. There is a shoulder milled into the cocking block to prevent it from backing completely out:
m_AR RVA 002.jpg

When all was said and done, I ended up with just over 1/2" of total adjustment range, which should be more than enough to tune the gun to whatever velocity I desire:
m_AR RVA 004.jpgm_AR RVA 003.jpg

Thanks a million, Sean! Not just for the great RVA, but for you and your wife (and MacKenzie) allowing me into your home, the great hospitality, patiently answering my numerous questions, and showing/explaining the basics of working with a lathe/milling machine. I learned more in an afternoon watching you than I have in the last year reading "how-to" articles. It was a most enjoyable afternoon, for sure (for me, anyways!). Only downside is I now have to convince my wife that I NEED those same tools. Maybe I'll have to get her that corner tub afterall...

Cheers,
Todd