tight upper/lower fit problem need help.

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[ARCHIVED THREAD] - tight upper/lower fit problem need help.

Posted: 10/25/2009 5:22:38 PM EDT

I have a RRA lower and CMMG 22 upper that the back takedown pin is super tight on. It's hard to get it pin in, and to take it down, I have to punch the pin through. I tried another upper (cmmg 5.56) and it was even harder than the 22 upper. Is it a problem with the pins or the uppers or ? I'm trying to figure this one out and could use some help.

Thanks.

Posted: 10/25/2009 5:35:13 PM EDT

[#1]

If it's brand new it will be pretty hard for the first 20 times or so before it limbers up. On a new build sometimes I think I did something wrong and have to double-check to make sure before I force the issue. It should get better if that's the problem, unless I'm mis-understanding you

Posted: 10/25/2009 5:39:04 PM EDT

[#2]

It's all new. I guess I was just too used to the military issue stuff where it's all been done before I ever thought about joining. I'll just throw some lube on there and see where she goes.

Posted: 10/25/2009 8:45:53 PM EDT

[#3]

When you use uppers from one manufacturer, and lowers from another, you are going to have tolerance differences that will equate to loose fit or tight fit. That is why the accu-wedge was designed for the loose ones. get a 1/4" chucking reamer and run it through the holes. Most times it only off by a couple of thousandths.

Posted: 10/25/2009 8:56:10 PM EDT

[#4]

I use a 1/4" round file and run it through the attached upper and lower until I get the fit I like.

Posted: 10/25/2009 8:56:11 PM EDT

[#5]

Double tap...

Posted: 10/26/2009 4:33:38 AM EDT

[#6]

I have heard that RRA lowers are super tight.

Posted: 10/26/2009 5:10:29 AM EDT

[#7]

Thanks for the tips, I'm going to go get a file this morning and try that out. Also I meant to say I put the upper on my uncle's CMMG lower––not his upper––and it was tighter.

Posted: 10/26/2009 5:49:31 AM EDT

[#8]

That's funny. (Strange, not ha-ha.)

I just assembled 2 CMMG lowers and they couldn't be a looser fit to multiple uppers.

Posted: 10/26/2009 6:09:32 AM EDT

[#9]

I've had problems with RRA lowers not fitting correctly (TOO Tight!) Thats why I ONLY use CMMG now!

PursuitSS

Posted: 10/26/2009 6:21:23 AM EDT

[#10]

Ok, let me think out loud for a second and end my own confusion.

I have a RRA lower and 22 CMMG upper tight in the rear pin. My Uncle got a CMMG Bargain Bin Rifle.
.22 CMMG Upper on my RRA lower is tight.
.22 CMMG Upper on his CMMG lower is tight.
His CMMG Upper on his CMMG lower is fine.
His CMMG Upper on my RRA lower is snug, but still able to break down by hand.

And I THINK my Bravo upper on my RRA is fine...but I only put it on there once and will have to recheck. This is the sucky part about keeping all this stuff at my folks house since I live in a condo.

So should I ream it out, or get a hold of CMMG?

Posted: 11/4/2009 1:13:34 PM EDT

[#11]

I just put together a truck gun and had the same issue with my RRA upper and RRA lower. come to find out the adjustable stock was worn (at the buffer stop) and was threaded to far into the lower to allow the upper to fit correctly. A little dremel time on the end of the buffer tube fixed the issue....

just a thought.

Posted: 11/4/2009 1:37:36 PM EDT

[#12]

I ended up reaming out both hole a bit and they come out pretty easy now, but still hold solid.

Posted: 11/4/2009 2:54:38 PM EDT

[#13]

RRA lowers are habitually tight. Use a rubber mallet or a hammer and a block of wood and beat the two together a couple of times until it loosens up. I like a good tight fit anyway.

[ARCHIVED THREAD] - tight upper/lower fit problem need help.

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