View Full Version : ar a15 receiver fit. Which brand has the tighest fit?

04-24-2010, 5:41 PM
I am looking to find out a set of receivers that have a super tight fit. A fit that there is little to no wobble between the receivers.

I have a complete doublestar rifle and there is significant wobble.
My friend has a stag and there is very little wobble.

what are some of your experiences?

04-24-2010, 5:56 PM
Have the factory "fit"/match a set for you... Maybe? I did that in the past.

04-24-2010, 5:57 PM
my cmmg upper and lower fitted pretty tight

04-24-2010, 6:06 PM
Well I have a Rock River Arms lower and a BCM mid length upper. The fit is so tight on theses two that when I pull the rear take down pin need to support the lower with one hand and tap the upper with the bottom of my palm to get the two to separate. I'd play musical uppers and lowers but my other two are RRA uppers ( a 16" & Varmit ) on Double Star lowers. :confused:

04-24-2010, 6:06 PM
My Stag 2HT is really tight. Funny thing is that I got the upper and lower 2 years apart.


04-24-2010, 6:09 PM
My tactical machining lowers with BCM upper all fit pretty snug, there is still a little bit of wobble but nothing that noticible.

04-24-2010, 6:09 PM
Buy an upper/lower set from Sun Devil (http://www.sundevilmfg.com/products.php) or buy just the lower, it has a Tension Screw, or on the cheap install a ACCU WEDGE (http://www.midwayusa.com/viewproduct/?productnumber=698479).

04-24-2010, 6:16 PM
I tried the acuwedge. however it didn't work very well.

04-24-2010, 6:27 PM
The tightest fit you'll get is from a billet matched set. Try a matched set from Mega.

04-24-2010, 6:27 PM
had a lar grizzly lower and a model 1 sales upper. and it was slop city.

04-24-2010, 6:31 PM
I tried the acuwedge. however it didn't work very well.

What issues did you have?

04-24-2010, 6:38 PM
The accuwedge will not work if the slop is from the front lug. The only thing that'll work on front lug slop is the O-ring method. Otherwise slap on another upper hoping it fits better.

04-24-2010, 6:38 PM
no issuses at all functionally, just would prefer to own an ar that feels more like a single piece and doesn't jiggle.

04-24-2010, 7:35 PM
My Valtor billet upper on my KD lower fit nice and tight together. Most billet uppers fit tight on good quality lowers as Ive been told.

Group B
04-24-2010, 8:07 PM
I thought I had seen it all.

In the April 20th Shotgun News, there's an article about these guys actually bedding the upper and lower receivers together:


04-24-2010, 9:43 PM
my spikes lower/dsa upper fit tight with no wobble or gap.

04-24-2010, 10:06 PM
Buy an upper/lower set from Sun Devil (http://www.sundevilmfg.com/products.php) or buy just the lower, it has a Tension Screw, or on the cheap install a ACCU WEDGE (http://www.midwayusa.com/viewproduct/?productnumber=698479).

+1 :iagree:

04-24-2010, 10:06 PM
my cmmg upper and lower fitted pretty tight

Same here, upper is CMMG WASP 16 inch and lower is CMMG MOD4SA. Fits super tight.

04-24-2010, 10:36 PM
my JD machine and RRA are freaking tight. need a hammer and punch in order to seperate the two when i first got it. its nto alittl easier. palce on table and put my wieght into it.

04-24-2010, 11:00 PM
Rock River lowers are known to fit very tight. I have built over a dozen RRA's and they do fit tighter than most lowers. Depending on the upper, sometimes you have to really force it together a few times before you can actually close the two halves. I have a Tactical Innovations lower mated to a Larue Stealth. The TI lower has a tensioning screw to tighten the receivers to take up the slack. Consensus says that the a loose upper\lower has no impact on accuracy but an overly loose upper/lower combo would bug me.

04-25-2010, 1:25 AM
a VLTOR MUR upper receiver will cure all your slop ills. the MUR has a nice tight fit on every lower that i've encountered.

04-25-2010, 1:30 AM
My 14.5 inch CMMG upper was extremely tight against a stag lower receiver. Had to run the takedown pins a few times back and fourth the first time to even get it to fit.

04-25-2010, 3:20 AM
My essential arms lower fit my DPMS lo profile upper like a glove. I think it just depends which lower you get. One made on a Friday or one made on a Monday.

04-25-2010, 8:39 AM
I have a JD upper and lower set. Its TIGHT.

04-25-2010, 8:54 AM
Rock River lowers are a tight fit. I still have to use a punch to break down mine.

The Director
04-25-2010, 9:16 AM
My STAGs are tight with no slop at all. They laugh (and so do I) at accuwedges.