Just received my expensive LMT upper from MSTN and all  my lowers exhibit a lot of side wobble,which are Colts, new OLY,and a WILSON/ROCK RIVER.

The fit probably varies some better than others.

My LMT 16" upper is slightly loose when mounted on my Colt 6721 Tactical Carbine lower but it doesn't have any noticeable play on my LMT Defender 2000 lower.

It would be interesting what other LMT owners have to say about it.

I have LMT and Bushmaster lowers, and the LMT MRP and LMT flat top uppers fit them all like a glove, my CMT upper and one Bushmaster upper have a very small amount of play but you never notice it.

Is a LMT upper most likely to have less side to side movement with a LMT lower? -- NO

 
SLOP from a LMT upper--nothing new.

Sold my LMT upper for lack of Quality--Now I only buy RRA stuff .

Quoted: Now I only buy RRA stuff .

Yes, you have to put them together with a rubber mallet!

I just got my LMT upper today and put it on my Bushmaster lower, and there is no diffeence in play between the new LMT upper and the new Bushy upper i used to have. The play is nothing i would be worried about. its very minimal.

Quoted:
Now I only buy RRA stuff .

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posted by edwin907
Yes, you have to put them together with a rubber mallet

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Sorry ed I have no idea what your talking about ??  

Quoted: Quoted: Now I only buy RRA stuff . -------------------------------------------------------------------------------- posted by edwin907 Yes, you have to put them together with a rubber mallet -------------------------------------------------------------------------------- Sorry ed I have no idea what your talking about ??

The RRA lowers are purposely tight at the rear lug, allowing you to have a zero play rifle after break in.  When new, some have had to use a rubber mallet to close them and/or get the takedown pin all the way in.  
Some folks complain about this but I see it as a good "feature", maybe a minor aggravation initially but a tight rattle free rifle many years down the road.
A friend bought a Rock River lower at a local shop (a few years ago), and then ordred a 20" varmint upper for it.  He actually didn't think I would get it together but finally did.  If you check his gun now, it's easy to break down, but assembled it's one tight mother.  
And his other 2 uppers (CMT, LMT) fit in it the same way, no play at all.  His buffer tube wasn't Loctited in, but I have read here that some were.

I'd love to get a RRA lower for this "feature" alone.

A guy at the range the other day had a factory new midlength RRA SS 1/8 16" Daniel Defense carbine that would shoot 1/2 MOA all day with the MR/T he had on it and Black Hills ammo.  I was impressed with the performance and quality of finish.  It was truly a pleasure to shoot.

Anybody have a LMT upper on a Stag/CMT lower?  How much play?

Only LMT upper I had measured .010 narrower  rear lug than others I have. RRA seem only to be a little flash heavy at the rear.
Colts about on.
I am surprised this thread has not been 'disolved' like the previous one.

Quoted: Anybody have a LMT upper on a Stag/CMT lower?  How much play?

None...also used my LMT upper on a BM and Doublestar w/ no play.  I guess I've been lucky, but I have zero problems w/ LMT.

Fit will vary from one example to the next but the one LMT upper I had was extremely loose on my LMT made lower (as well as other lowers).

As other have pointed out, a loose fit does not effect anything but if you don't like (I don't) you can install a #7 O-ring around the front lug of the upper before mating it with the lower. That will tighten up it very well.