a topic about 'Frankenstein' ARs...


November 8, 2008, 03:30 PM
It's always nice to see and hear of someone's new Colt, or new Bushmaster, etc.

But, what about people who grab a different-brand upper and lower and slap it together?

So, what kind of combinations have fellow THRers gone with, and how do they work? Any problems with color matching or fitting?

My first and only AR right now is a Del-Ton middie kit on a doubleStar lower. You guys?

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November 8, 2008, 04:41 PM
A year or so ago,I got an old '70's (yet still new) Colt tri-guard upper from CDNN for $369 IIRC, and hunted down the best deal going on a Rock River full lower and BCG, for the same price ( which was a really lucky break, as this was not only the best price going,but everyone else was out of stock.)
The front pin clicked right in, but the rear post barely jammed up in the recever. I took a file to the back edge for 10 seconds or so, you could barely even see what I'd done, but the upper then dropped into place perfectly, and it's been as slick as the proverbial owl excrement ever since !!:D

November 8, 2008, 04:49 PM
I currently run my LMT Monolithic Rail Platform upper on a Rock River Lower. Seems to work just fine, and if there's any variation in coloration, finish or other cosmetic issues, no one's ever noticed.

November 8, 2008, 04:53 PM
My AR is a "franken-gun," I suppose.

I have a Del-ton M-4 that I built on a DPMS stripped lower.

My only complaint was that the gas key was not staked on the Bolt Carrier. But you know what? Staking is easy and quick.

Mine runs fine.

-- John

November 8, 2008, 05:58 PM
I've got an LMT upper on an Essential Arms lower with a RRA lower parts kit and a CMT bolt. Works like a dream, colors match perfectly.

November 8, 2008, 06:02 PM
I've got custom, DPMS and Alexander Arms uppers, with a mix of DPMS and RRA lowers.

I though that was how everyone did it, do some people actually buy complete guns without mixing and matching?

November 8, 2008, 06:15 PM
Delton on Essential arms lower, with stag LPK and RRA buffer& stock

November 8, 2008, 06:18 PM
Well, my ar is fully built from the factory, but the upper and lower have VERY different colors and textures.

November 8, 2008, 11:20 PM
DPMS lower with a DPMS parts kit, MIAD grip and CTR stock, BCM upper with a CMT BCG.

November 8, 2008, 11:34 PM
As long as they are all standard military specification, they all fit together and operate well. The fire control group in the lower will hit the firing pin correctly on any upper. Just make sure they are standard commercial upper and lower receivers built to common mil spec. Nearly all of them are.

I have six such rifles. Only one of them had trouble fitting together: Generic milspec upper on a PWS lower took tiny bit of filing on the upper at the rear takedown pin hole. (I filed the upper because I didn't want to mess up the lower, since that's the registered receiver. That turned out to be wise, since the upper was the one slightly out of spec. I only had to remove about 5 or 6 thousandths of material.)

Once I assembled a bolt carrier group from assorted spare parts, and the bolt lugs didn't want to lock into a barrel I got from a gun show vendor. So I swapped bolts from another rifle and everything worked right. But this was not the result of buying a complete upper and a complete lower and mating them. This was built up from spare parts of unknown origin.

Certain Colt commercial rifles were made with larger pins (so you couldn't 'accidentally' convert them to full auto M-16). You need offset adapter pins to fit them to modern commercial receivers from any current source.

November 8, 2008, 11:34 PM
They should work just fine if the parts are from reputable manufacturers.

November 9, 2008, 12:41 AM
I though that was how everyone did it, do some people actually buy complete guns without mixing and matching?Yes, that's what I did with my first one, because I've seen too many people with Frankenrifles at the range pop them open about every 7th shot to tinker with something, and I bought my rifle to shoot. Since I didn't have too much experience with the platform, but wanted to have an AR, purchasing it and getting the manufacturer's warranty was important to me--that, and I also knew that it would work.

But now that I have my stripped lower after the 4th, I'm looking into building one, simply because 1) I can and 2) I already have a working AR, so a project piece could be fun.

November 9, 2008, 04:42 AM
I have a RockMaster (or is it a BushRiver?). RRA midlength flattop upper on a Bushmaster lower.
M4 stock, Miad grip and reddot.
Rifle has been 100%.

November 9, 2008, 08:40 AM
I've got one CMMG upper on a double star lower, shoots just as good my complete CMMG rifle.
I think the quality of the parts you use matters more than if they match.

November 9, 2008, 02:23 PM
Colt M16A1 upper w/ 16" Bushmaster barrel on a DPMS A1 lower from 2000. Works great.

November 9, 2008, 03:05 PM
I wholly agree with that. But, I was always wondering if anyone noticed any fitting issues. The only thing that sucks is not having the warranty, but any breakable parts are cheap anyway, and I've yet to see a decent barrel get shot out even by the old-timers who've had their rifles for 20 years.

Right now, I'm sitting on a CMMG stripper lower. I'm looking at getting a CMMG upper, with either Stag or LMT or BCM bolt and whatever decent lower parts kit I find.

November 9, 2008, 06:31 PM
delton upper with an anvil arms lower, no ftf through 500 rounds. Finish is different under close inspection but 5 feet away you cant tell, just looks evil and black :)

This is my first on and i wouldnt consider it a "project". Took perhaps an hour to assemble the lower and i bought the top complete

Deer Hunter
November 9, 2008, 07:45 PM
Delton upper with DPMS/RRA lower.

November 10, 2008, 01:36 AM
Mine is a Bushmaster ORC upper with a Del-Ton lower.

November 10, 2008, 12:56 PM
I get alot of fun out of building my AR's. I use DPMS lowers and parts from just about every reputable maker on the market. I can say that mine are very reliable and accurate. They go bang when I pull the trigger and ingest anything I chose to feed them. I'm not saying that complete guns are not good I just like doing it myself.

Dr. Tad Hussein Winslow
November 10, 2008, 01:07 PM
Except for Colt's, they're like Mr. Potato Head - mix and match and it all works fine. :)

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