Are ar15 uppers and lowers compatible.

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josiewales

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So I've never had an AR but I would really like to get 1. My question is: does an AR upper fit any AR lower?
 
As long as you're talking AR15, yes. Once you get into the AR10 things are much more confusing.

The exception with this is some of the older Colt receivers that used oversized takedown pins. As long as you're talking new manufacture, it isn't an issue.
 
Pretty much, but remember, there are many makers, and sometimes the fit is a bit loose and sometimes a bit tight, but for the most part you will not have any problem. They should all made to the same specs.
 
Only one you need to be aware of are the colts as they had a different size takedown pin set for awhile. Otherwise yes they will all fit (in theory). There is always the chance of tolerance stacking but rarely an issue.

Pretty much, but remember, there are many makers, and sometimes the fit is a bit loose and sometimes a bit tight, but for the most part you will not have any problem. They should all made to the same specs.

There are some nice lowers such as mega arms which IMHO make the best stuff out there at the best price point. They have a tension screw throw the bottom with a rubberized tip to help deal with any possible slop. Even the tightest fitting forged receivers will loose. Up over time. Now billet is heavier but much tighter tolerances and considerably more money (getting better all the time on price) won't do this.

For the most part a lower is a lower as long as they are in spec and while some you pay for a little added features such as the tension screw most you're just laying for the roll mark and finish. Uppers, all kinds to choose from with various features, side chargers, forward assist delete, modular etc.
 
I discovered I can save considerable $$ by buying the upper and lower separately. Thanks guys, all I wanted to know!
 
That too. But I was mostly talking about uppers for $400 on gunbroker and complete lowers for $150.
 
In reality and counter to several of the comments, the most noticeable difference in a so called "franken AR" is in the resale value. If you buy a factory built rifle and keep the receipt, the resale would be higher than buying separate upper/lower and pushing the pins.
I have several AR rifles of both home made and factory made. Honestly, I challenge anyone to determine which is which w/o looking at the logo. I got into(and out of) the AR market before the prices started edging up the last couple of years. At that time, an M-4(gery) carbine could be put together for $425-450 using a new upper and lower. I won't say they're top notch but they function and are sufficiently accurate for most uses.
 
^^ That is true. Just have to save up longer.
Not a whole lot longer. I'm in that boat with you, and have to play the waiting game. I can't get either a PSA or Colt 6920 til early December, but the feeling you can get knowing you got an awesome rifle like the Sport/or any comparable rifle in that range. You can build a quality gun, but as much as I've researched, $550 ain't quite getting it done. Close, but you're missing out on 158 steel bolts, proper testing, Melonite or chrome, even proper sights and gas tube length options. If you only want a rifle that goes bang, by all means. I'm not the guy that's going to tell you to save another several hundred more before you can reach the pinnacle of a good rifle. But a hundred, more for tax, and you're into a built rifle with a warranty that is plug and play outta the box. In that regard, the Sport would be a great star for sure!!!
 
PSA upper with FN barrel, mil-spec BCG is $400. It's just a plain jane flat top with plastic hand guards, but what is it lacking in quality?

Link to that?

Link to the lower necessary to complete the $550 rifle?

Is this $550 rifle being shot without sites?
 
The appendages for the dust cover hinge do not exist on the M&P15 Sport, at least per the photos I looked at.

So, no dust cover on that model.
 
If you don't mind a polymer lower, there are a few companies that make them: Plum Crazy, New Frontier and ATI. All three complete lowers can be had for under $150. Del-ton, DPMS, and PSA uppers can all be had for right around $400-450. A $500 AR-15 is possible. Will they be able to stand up to a Colt under battlefield conditions? Probably not. Nor are they designed to. Your $500 AR is just fine for the range or home defense.

PSA had a sale on their carbine uppers, $269 for a barreled upper, just missing the charging handle and BCG. $17 for a handle and $120 or so for a BCG, and there is your PSA $400 upper.

If you want milspec, this is not the way to go, but if you want a functional AR on a budget, this set up is fine.
 
If you don't mind a polymer lower, there are a few companies that make them: Plum Crazy, New Frontier and ATI. All three complete lowers can be had for under $150. Del-ton, DPMS, and PSA uppers can all be had for right around $400-450. A $500 AR-15 is possible. Will they be able to stand up to a Colt under battlefield conditions? Probably not. Nor are they designed to. Your $500 AR is just fine for the range or home defense.

Would you mind providing a link to these components that could build a $500 AR?
 
This depends on your intended use.

For most people, no, the local range does not require a dust cover for any good reason
Unless you plan on literally dragging it through the mud or shoveling dirt into the ejection port with the bolt held open, the dust cover is a solution looking for a problem. It was added in response to a problem that had nothing to do with foreign matter entering the action.
 
PSA bolt carrier group $139.95
http://palmettostatearmory.com/index.php/m16-bolt-carrier-group.html

PSA charging handle $15.95
http://palmettostatearmory.com/index.php/ar15-m16-charging-handle-6332.html

PSA upper $269.99
http://palmettostatearmory.com/inde...ped-upper-without-bcg-or-charging-handle.html


New Frontier lower$109.95
http://www.joeboboutfitters.com/PlumCrazy_C_15_Composite_Lower_p/pc-lowerassembly.htm

A rear sight can be had in dozens of places for about $15.

Fully functional AR15 for just shy of $550.
If you need me to Google Delt-Ton, DPMS, Plum Crazy or ATI for you, just let me know.
 
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