LMT MRP Issue

[Defender3]

I bought a new LMT SOPMOD lower from VA Arms and a slightly used LMT MRP CQB upper. The upper arrived and I noted that there's a level of resistance that can't be correct for the fit between the two. It's a very tight fit to the point I have to really force the upper and lower together. My other LMT is tight, but not to the point I'm using leverage to try and get the two together.

I don't have gauges so the best I could do was try the upper and lower against another LMT that I own. The picture shows the new lower (Lower 1) with the MRP Upper (Upper 1) at the point binding occurs. If I was to hold the upper and lower up at that point, you could see daylight between the two all the way across the horizontal plane where they meet; there is no apparent point of binding across that plane. I have another LMT that I took apart to test (Upper 2 and Lower 2). I also have a bare LMT Upper (Upper 3). It seems clear there has to be an issue in the area of the front pivot point on either the upper or lower.

Lower 1 and Upper 1 = Tight
Lower 1 and Upper 2 = Okay
Lower 1 and Upper 3 = Okay

Lower 2 and Upper 1 = Okay
Lower 2 and Upper 2 = Okay
Lower 2 and Upper 3 = Okay

Clearly Lower 1 and Upper 1 just don't get along. Any ideas?

http://img.photobucket.com/albums/v501/defender3va/DSC_0298-1.jpg

[ICANHITHIMMAN]

deleted do to unclear information by my self

[kwilkin]

Do NOT file down the tabs.

I contacted Gene Swanson about the same issue. The tabs are put there to give the upper a tight fit--you won't get rattle at all.

That said, you just need to put downward pressure on the upper (right over the top of the takedown pin, where the rear BUIS would be) while inserting the takedown pin. You should be able to get it to closedown with this method--works for me every time.

[LowSpeed_HighDrag]

How often do people with MRP's and different lowers run into this issue?

[ICANHITHIMMAN]

Do NOT file down the tabs.

I contacted Gene Swanson about the same issue. The tabs are put there to give the upper a tight fit--you won't get rattle at all.

That said, you just need to put downward pressure on the upper (right over the top of the takedown pin, where the rear BUIS would be) while inserting the takedown pin. You should be able to get it to closedown with this method--works for me every time.

Kwilkin thanks for the info man Im going to delete my first coment cause you heard it from the horses mouth. See there contact Gene or ryan like we said. My suggestion may be the wrong one. Mine is a bit tight too and the pads are shinny from rubbing.

Jon

[kwilkin]

No problem. My tabs are shiny, too, but I'm not sure that's a problem.

To answer another poster's question: I have only tried my upper on a Stag lower and it required the downward pressure mentioned above. I have tried it on a Spike's lower, but it wouldn't take the pivot pin; I attributed the Spike's lower to being more out of spec than the MRP upper (as Gene indicated: "tolerance stack"). I actually expect most lowers to require the "downward-pressure" technique, but I haven't tried it beyond these two.

I like that the tabs make tight the upper-lower fit, but it can be a pain when you want to take off the upper. I have been using a punch to separate them, but I bet the same downward pressure can assist with removing the takedown pin as well.

[Frank Castle]

Mine is pretty tight on my Noveske lower- performs flawlessly.

[ICANHITHIMMAN]

I should have mentioned I have a PWA (LMT) lower and its very tight as well

[LowSpeed_HighDrag]

This is disapointing as I almost exclusivley use Spike's lowers. I'm surprised LMT is allowing there products to be so tight that it doesnt work in some cases.

[Defender3]

Thanks for the info guys. I dropped Gene a note at LMT and asked the same question. FWIW, I can get the upper and lower closed, it just takes lots of downward pressure to get the holes lined up and the pin in. Then, I need to use a punch to get the back pin out!

[ICANHITHIMMAN]

Thanks for the info guys. I dropped Gene a note at LMT and asked the same question. FWIW, I can get the upper and lower closed, it just takes lots of downward pressure to get the holes lined up and the pin in. Then, I need to use a punch to get the back pin out!

Mine was like that at first but after about 250 rounds it is still tight but I can push the pins out far enough to get the feed lip of the mag under the edge abd pull her the rest of the way out.

[seabyrd6]

How often do people with MRP's and different lowers run into this issue?

Mine too!- it's is OK-

[Defender3]

I spoke with Ryan at LMT today and he believes this is a stacking of tolerances issue that will not affect form, fit or function. He did not suggest I take the pads on the upper down as that would negatively affect its fit to other lowers. Thanks to all who replied.

[Maize]

Mine too!- it's is OK-Same here

[LowSpeed_HighDrag]

I got my MRP upper today. Fits snugly on my Spikes lower, but it fits all the same.

[ra2bach]

This is disapointing as I almost exclusivley use Spike's lowers. I'm surprised LMT is allowing there products to be so tight that it doesnt work in some cases.

I bet they work just fine with their own uppers...

[kwilkin]

This is disapointing as I almost exclusivley use Spike's lowers. I'm surprised LMT is allowing there products to be so tight that it doesnt work in some cases.

FWIW, my MRP upper won't take the pivot pin on my Spike's lower. It takes my Stag lower just fine.

Honestly, I attribute it Spike's being more out of spec than LMT. I have read (sorry, can't cite the source) that Spike's may put additional material near the pivot pin for greater support or something. Not sure, but it's one strike in my book against Spike's. Although, my Spike's does fit any other standard forged upper I have tried (KAC, Colt, LMT, Stag).

[scottryan]

Grease it up and hammer it down with a rubber mallet.

[wetidlerjr]

Grease it up and hammer it down with a rubber mallet.

http://img.photobucket.com/albums/v114/wetidlerjr/Smilies/speechless-smiley-040.gif



...:D