Why do some insist an AR have matching upper and lower?

Some think it reduces the rattling or loose fire between the upper and lower. IME, this varies.

Some manuacturers, LaRue comes to mind, are well known for their tight upper to lower fitment between their own upper and lower receivers.

Resale value would be one thing. I bought a CMMG stripped lower for my radial delay blowback build just so that if I ever sell it, it says the right thing on the lower.

Hmm, I'm not sure I know anyone who insists on matching anything in an AR. They often have one or two, but they were generally bought that way, not required to be that way.

Anything is possible, I suppose.

People insist on all manner of things. I insist on a number of things. Like Taco Bell is not TexMex. That every bit of an AR match is not one of those. To each their own.

I would have guessed that AR owners are the more tolerant and forgiving demographic of gun owners in terms of lil cosmetic/fit and finish issues. Uppers and lowers are often mismatched, especially if they are of a different make.

There are those however, that would never dream of having an upper and lower of a different make. I could see Colt owners being especially fussy about something like anodizing tones, U/L fitment, Logo Depth, machine marks, GK staking, etc.....

DustyGmt said:

U/L fitment

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I generally recommend a colt for a good entry priced but reliable and high round count carbine. Or at least I did for most of the past 20 years..... but of the several hundred I've seen or fired I've never seen one with a great upper to lower fitment. Most have actually been pretty poor. Lol. I have a few 6920 that you could shake and rattle when unloaded. Not that it matters. They have been very reliable. I see colt guys getting all up tight over the other things you mentioned for sure. But never heard a one of them mention good upper to lower fitment.

Pretty sure colt is why "accuracy wedges" exist. Lol. Back then you could buy a Colt or an Oly. And the OLY had the better fit by far.

For the 100 round total that majority of AR see in their lifetime.....a Lorcin or Clerke AR would last just fine.

As far as matching upper/lower i wouldn't care about the name per se.. But I wouldn't buy a franken-gun either. Who knows what parts and what "gunsmithing" went on. So I have always bought complete guns other than a few complete uppers.

@crestoncowboy yeah come to think of it, I think I heard the same thing about the U/L fit on Colts, I don't have anything against Colt really, I almost bought one but it was just a lil more than I wanted to pay. I guess it came across like I was specifically picking on Colt but any brand loyalists are guilty of the same thing. It's XYZ brand AR or go home!!!! I don't mind a franken gun, as long as its me who assembled it......

DustyGmt said:

@crestoncowboy I don't mind a franken gun, as long as its me who assembled it......

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I have bought several just to rip them apart and reassemble them so that I know what’s been done. So far no really crazy shenanigans except for a pie plate used as a barrel spacer to get things lined up properly. It went back together how it came apart by the way, because I knew what it was doing when I bought it and I didn’t want to mess up a 1/2 MOA upper. Traded that one for a 5.45x39 upper and a span can of Russian ammo.

DustyGmt said:

I guess it came across like I was specifically picking on Colt but any brand loyalists are guilty of the same thing

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Oh yeah. I get it. And I was there when the AWB ended and I saw all the tier charts and all that for AR. I know exactly what you was referring to. Mil spec vs carpenter bolt vs f marked sight vs commercial receiver tube vs h buffer vs............ of course Windham bushmasters/ Colt/ and Oly were about all there was to begin with. I wouldn't even say I'm a colt fan either. But they consistently made a reliable (if inaccurate) rifle where other companies struggled to be consistent. Most of my Colts though have 1/4 inch of slop in the u/l fit though. Very bad actually. I try to tell people that it really makes no difference. But they would choose my old 2000s oly over the colt just because of it. Lol

I'm the guy who may show up to hunt rabbit with a Benelli/ Browning/ or Beretta o/u or I may bring a stevens. I'm no brand snob.

The only time that it really matters to me is with a LFAR / AR10 build - there's enough dimensional variance between manufacturers (even within the two main patterns) that it makes sense to get the upper and lower receivers from the same folk.

Tirod said:

We don't do that with pistols, if anything the contrary, non matching has had it's ups and downs in popularity all the time. Now, with cerakote, we see deliberate mismatching in color and even finish. Stainless, blued, matte bead blast, vs black, nickel, chrome, blued. Seems like endless combinations.

With AR's tho, it's a thing, many think they have to match, and variations in a specific color by different makers aren't tolerated much, if at all. In the 60's tho, mismatched M16's were common, light gray (not black) uppers vs dark gray, or vice versa. It's remarked on looking at older pics, and for some, building a correct vintage homage, they follow it, even using dye remover to get the correct differences in tone.

While others save up and get a set anodized in the same batch to match as closely as possible.

What do you prefer, and who has pics of mismatched AR's? I can see a benefit if camo is the desired result.

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To me, the upper and lower receiver of an AR look like one piece, until you take the gun down for cleaning. Everything lines up visually, top to bottom.

For instance, a Marlin 39 rifle also has a split receiver for take down purposes. If the right half was a different color than the left half . . .
Well that's how I see an AR receiver, even though the split is in a different place.

When it comes to pistols, the slides clearly don't look like one piece with the frame. Especially when the slide is steel and the frame is polymer. Plus, a slide is a moving part, which makes me think of a contrasting colored bolt in a bolt action rifle. So having the slide and frame of a pistol in different colors or finishes seems to make more "aesthetic" sense to me.

Of course, people are free to do what they want with the appearance of their own possessions and all that.

There are some reasons that people want the upper and lower to match but it all comes down to personal preference. There really isn't a right or wrong answer or approach to putting together an AR. And as long as it safely goes bang when you pull the trigger everyone can have it their own way. And that is part of the beauty of the AR. There are 1000s of ways to configure them.

…What do you prefer, and who has pics of mismatched AR's? I can see a benefit if camo is the desired result.

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You asked for it…urban camo.

25-20 WCF said:

You asked for it…urban camo.

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Infectious design, huh? Yeah, I generally puke when I have an infection.

I have to admit I have 3 stripped uppers that I bought someplace that the anodizing is a distinctly grey color compared to all my lowers and handgaurds and it bugs the crap out of me

crestoncowboy said:

...Most of my Colts though have 1/4 inch of slop in the u/l fit...

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The quarter inches on your scale must be a lot smaller than mine.

If I am not refinishing to another scheme, I’d prefer the receivers to match. I would ,and have, gone so far as buying the handguard and all at once from the same company. Not only for the color, but like noted before, for the same company machining fit.
And the Aero Matched Build set came in a beautiful dove grey, for anodized black, all pieces the same color, and it snicks together like a pair of scissors. It shoots the same, or a little better, than the rest of my ARs.
My first AR came as a “Blem” Adams Arms. The upper is slightly green in sunlight. The rest is superb, and as tight as any of the rest I built from non matching uppers and lowers.

As for some of the billeted receivers, usually the lines won’t line up between the two. This may or may not be aesthetically pleasing, but it will also leave shaper than normal edges that might rub the wrong way. Or it may accelerate “battle wear” which seems popular lately, which I abhor.
Not to mention that a LeadStar skeletonized looks pretty silly on a Sharps Warthog. Why save weight to pack it into a mag well? Or maybe the mag well is so heavy they needed to save weight?

My socks must match too.

MistWolf said:

The quarter inches on your scale must be a lot smaller than mine.

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Lol. I usually use a vernier or feeler for distance. But the ¼ inch was side to side i guess you could say. Say you hold the rifles with an optic mounted. Then go side to side with the optic. Will Rock ¼ inch. Not a ¼ inch gap anywhere by any means.

My Colts have more play that way than any other brand I own. Currently that is a Daniel defense, a few colt and a couple Anderson. Plus my first AR. An Olympic. Id still choose my colts just as quick as any high dollar brand I've shot. And I shoot a lot. To me its like the "glock kiss" that people cry about. It is a cosmetic non issue

Same reason some people like their car painted in the same color than having a car like this

Don't care. Mine all get coated in Krylon Khaki anyways.

Black rifle guys never looked through modern night vision, I guess?

If it’s someone else’s gun, I have no objections. But I’ll not buy a mismatched AR personally unless I know who built it and was assured they knew what they were doing and used quality parts.

I’ve seen outstanding home built AR’s and a I’ve seen junk. And I admit I cannot always tell the difference…so I move on.

Black anodizing is easier to match versus any other color. And that is part of the reason you see so many different shade of grey on AR receivers. And even black can vary from batch to batch. The last AR22 I built was with an Anderson upper and and Anderson lower that were bought at different times. Same manufacturer but there is a slight difference in the anodizing between the upper and lower. IF you want both to match perfectly then painting or cerakoting is your best option. While is is easier to get black anodizing to match, there is no guarantee that it will be a perfect match. It is just the nature of anodizing aluminum.

As far as how the upper and lowers fit together, I have seen everything from very tight and hard to get the pins in to very loose. And that is from a lot of different manufacturers. Yes all AR's are built to a standard set of specifications but there are allowable tolerances.

If I'm buying a whole rifle as a piece from S&W, Ruger, or any of the other thousand makers, having the upper and lower match the same shade of black is an indication of good quality control to me. Same if I buy an upper and lower together from Aero or whomever. But if this is an upper and lower I'm piecing together, it doesn't bother me at all. I have a couple BCM uppers that might not have the exact same shade and level of matte as Aero lowers, and it doesn't bother me at all.