Sun Devil just sent me some of their new billet lowers. What makes these interesting is that they have a tensioning screw in the bottom of them that applies pressure against the upper receiver. This screw removes all the play between uppers and lowers! Below are some pics of them.
C4
Evolution? Did they change something from their previous billet lowers? Hasn’t all their lowers from before have the tensioning screw?
I have 2 of their previous design, and both don’t have the “tensioning screw” feature.
Interesting, I could swear my buddy has one of their billets from a while back and it had a screw-tension in it…i’ll double check
Correct. This something new that they just came out with.
C4
Grant how do these fit with a standard upper? I know the lowers are reinforced in a different way.
Thanks
Fit pretty good from the CMT’s that I installed in them. It really doesn’t matter though because of the tensioning screw.
C4
great idea. I’m sure it will be standard issue on all lowers in the near future.
I thought it doesnt matter if there is some slop 
I love the meat tenderizer on the front. Nice touch.
I want one!
Jump back Jack, its’ mine!
You take that one and work out all the bugs. I’ll wait for the next “revision” 
Apparently Mega Machine sources Sun Devil.
So you set the screw and lok-tite it in place?
what happens when the steel screw rubs against the aluminum pin hole lug and wears? Or does that not happen? Blow torch the lok-tite and retighten?
I was wondering the same thing. I have a Mega lower on one of my ARs, and I use an AccuWedge to keep things tight. It cost less than $4, puts no wear on any surfaces, and is somewhat self-adjusting given that it simply compresses less over time as wear between the parts increases.
No red loctite is used and the end of the screw is flat so it really is not going to wear into your upper receiver IMHO.
C4
Actually, unless there’s a perfect fit, any movement - up or down or side-to-side - of a steel screw against aluminum will create some wear. However, given the amount of aluminum on the bottom lug and the small amount of wear involved, it’s a distinction without much difference. I wouldn’t worry about it. But I do think you’ll get a better fit with a compressible AccuWedge.
I’m not worried about the small steel screw wearing away the entire pin lug. I’m considering that any amount of wear may end up negating the “tightness” you get from tightening the screw against the lug. It would then require retightening and that won’t be easy.
Exactly. You said it better than I did. That’s the point I was trying to make about the AccuWedge being self-adjusting because as things wear over time, the pin will still compress the AccuWedge but not as much as before. Also, given the compressible nature of an AccuWedge versus the non-compressible nature of a steel setscrew, I’d consider the AccuWedge as more user friendly (takes less “adjustment”). If an AccuWedge isn’t trimmed exactly perfectly, you can still compress it enough to push in the takedown pin. If a steel setscrew isn’t set exactly perfectly, there’s no way you’re going to compress it enough to push in the takedown pin. And if the setscrew is set even just a little bit too low, you won’t achieve a tight lockup, which defeats the purpose of the setscrew.
Frankly, the setscrew idea is an interesting engineering approach, but for me the AccuWedge seems more practical and effective.
I’d have to say the POF right side bolt release is probably the next evolution… Having a tight lower to upper fit is nice and makes for a solid feeling gun, but that shooting hand index finger bolt release is pretty damn cool.