What lower for CMT upper?

AR/M4 AR Technical Discussion
1

Just started my second build on a CMT upper reciever. My first build was also a CMT upper mated to a Superior Arms lowers. Its a nice lower but has a little bit of play between the upper and lower. I tried a friends RRA lower on my upper the other day and the fit was very nice and tight like a gun should be. So I went to my local dealer to order a RRA lower for my new upper and they say it will be at least 16 weeks.:eek:

So my question is what other lowers will fit CMT uppers as tight as the RRA lowers? Thanks.

2

I have a CMT upper and Mega lower. Fit is perfect. It isn’t so tight you can’t get the top and bottom together, but there is zero play between upper and lower.

Upper and lower purchased from Rainierarms.com (+1 on those guys as well)

3

Stag Arms is CMT. Global Tactical lowers are CMT too. I assume there are others.

4

I have a Stag/CMT upper with a CMMG lower that looks and fits good. The flash on the camera made the colors look like they don’t match, but it actually matches pretty good.

5

I don’t think there are any other lowers that would fit tighter than RRA.

I have both RRA upper and lower and it is very tight at first but now still no play and still have a snug fit.

Other CMT manufactured lower that I know of are:

Stag Arms
Compass Lake Engineering - CLE
Global Tactical Supply
High Standard
MGI
Noveske
Ratworx
RRA
S&W
Wilson Tactical
(new) Century

6

thanks for the info.

7

The play between an upper and a lower matters not (FYI).

If you buy a STAG lower, it is the same as getting a RRA (and is cheaper).

C4

8

I know it doesn’t really matter, but the little bit of play still bugs me a tiny bit. I can’t help myself.

9

on the other hand, if you need a vice to get both pins through… you might have a problem -

Right GotM4? :wink:

10

New guy here … I also have Stag M4 upper on a MEGA lower. The match is Not perfect color/finish wise. The upper is pure milspec, the lower is much more satin velvet lack look to it. It went together perfectly with a RRA trigger group. It hits Azone out to 200yrds and is 100% perfectly reliable. Happy guy here. Got the upper from john @ Rainier Arms and he his the ultimate gentleman. I think Id go STAG lower next time and without any doubt the same upper.
Harold H.