I'm considering buying a 20" or 24" National Match RRA upper and putting it on a Colt 6520, 6920 or 6721 collapsable stock lower. Will, it just pin right together? Any special adapters, pins, or concerns that I need to take into consideration that I might be ovrerlooking??
(other then the Colt's parkerized finish not being as good as the RRA ) I hate on the job learning.

i dont see where it would differ from any other ar upper/lower. as long as the colt lower has the std pivot pin

Yea, that's one of the questions in mind. I don't know a pivOt pin from a pivAt pin.... or if Colt has a PivEt pin???
I hate to buy stuff and be surprised with half assed arangements . I have never bought seperate halves and monkeyed around with this stuff to know anything about it.

Well for one thing an NM upper will only be 20 inch, that is the length for Service Rifle.  Next, do you have a National Match lower, with a two stage trigger?  If you are trying to build an NM compliant rifle, the trigger must not be less that 4.5 pounds.

Which sights are you considering for your upper? 1/2X1/2 or 1/4X1/4?  How about the aperture, 0.030 or 0.040?

Are you looking at High Power Competition?

Sig,

I'm an accuracy nut, but don't ever plan to compete. I want a rifle that has most of the evil features. But unlike my Colt carbine 6721 or my 6920 (which shoot about 1 1/2" groups at 100 yards), it will hopefully deliver 1/2" to 3/4" at 100 yards. The RRA has the bayo lug, flash supressor, standard front post, and a free floating handguard that looks like a standard military handguard (which is fine with me) If I put a Colt carbine collapsable stock lower on it, I will have one mean looking war whore of a rifle that should shoot some impressive tight groups.

I realize not everybody would wish to put a collapsable stock on a 20" upper. But, that's my preference.

I just want to make sure I don't end up having to use some kind of weird adapters or something.
 

VaniB, I hear and understand what you are saying.  I am also enthralled with accuracy and as such, I like my barrels to be free of any uneccessary accoutrements that may alter the harmonics.

So, even though barrels are once again available with the various things you mentioned, I like mine very plain but highly accurate.

To each is own.  Have fun and shoot straight.

I think the Canadian military carried a setup similar to what you propose;
20" standard weight barrel with a collapsible stock.

I put my Rock River Arms UTE 2 upper on my Colt LE6920 lower to check fit for a friend, and the two fit together very snug.  I was quite impressed with how well they fit together.  But then agin CMT is a sub-contractor for both Colt and RRA, so it's not too suprising that Colt and RRA receivers fit so well together.



Hope this helps.

USMC03,

I know that the 6920 (like mine) is held together with large pins. I presume that the RRA has small pins?  I'm assuming then that you had to buy special pins?


(yea, I know I can research and find out this stuff out myself, but hoped someone could fill me in on the pins before I go bothering the vendors for information when I'm not ready to buy anything from them yet)

I personally would not DESECRATE a COLT lower with an RRA upper!

Quoted: USMC03, I know that the 6920 (like mine) is held together with large pins. I presume that the RRA has small pins?  I'm assuming then that you had to buy special pins? (yea, I know I can research and find out this stuff out myself, but hoped someone could fill me in on the pins before I go bothering the vendors for information when I'm not ready to buy anything from them yet)

My Colt LE6920 has standard size pins.  My LE6920 is marked LEO only (it was purchased during the ban).  I don't know if Colt has changed the specs on these guns or not.

USMC03,
Perhaps I'm confusing the various different pins of the receiver halves with the trigger pins. I haven't dug my safe queens out to examine them closely since I'm not fully decided what I'm buying yet. Thanks.

MARKM,

I've been a Colt snob for 11 years now.   I have only owned  3 AR15's in my life, and they are all Colt LEO carbines.   IT TOOK A LOT OF WORK AND EFFORT TO OWN THREE THAT I COULD BE PROUD OF. Yes, I'm fussy....and what I have discovered is that if you want a really nice Colt, it's going to be hit and miss with what you find in the unopened box shipped to your dealer. Out of the 3 carbines shipped to my dealer, the 6520 that I bought 11 years ago is nice, the 6920 bought last year was loose all over and needed factory service, and the 6721 also bought last year had a finish that was hazy, 2 tone, and contained casting pock marks. It looked like crap so I sold it! It cost me an additional $215 to look over another 3 in their boxes at a gun show, and find a nice replacement.

In the past I have never even considered an RRA, because it wasn't a Colt!! Well, now after hearing from sooooo many folks how super tight these rifles are, how accurate they are, and how well the finish is on them.... I'M A BELIEVER! At least enough  to want to examine one the next time I'm at a gun show. ( instead of being a Colt snob and walking right past the RRA's)

I wonder what it is you don't like about the RRA? Or is it just blind devotion to the Colt name as I suffered?  

....so nobody else takes exception to Markm's comment? I could better understand it if he compare a Colt to an Olympic Arms!...but to an RRA?