I am looking at getting either a Aero Precision or Vltor Upper receiver.  Will consider others of course but cost is a factor always but so is quality.  The Aero is $70 shipped and the Vlor is $155 shipped. 

Also might ask in the EE on upper recievers if anyone has a spare they will part with.

I have a Rail on the way and a Barrel that will be here in 4 weeks.  I also have a CH from BCM and BCG from Aero Precision right now.  Rear sight well I have a Knights rear

Are there any issues with Aero Precision upper recievers?  I have their lowers and they work, I am just wondering if I should look else where or a non name brand one.  SAA had assembled uppers going for $62 with cerro forged marking and the Flag but it might get painted anyway.  I like Paint.   

This will be used with a KAC URX II 10.75 (always wanted one thanks Kaltesherz) and a 11.5 inch barrel Black River Tactical 11.5 barrel (6P rifling intrigues me).

I have been typing to the owner through email and I think they are on a good path with the 11.5 inch barrel so I think it will be good for my GP rifle when I do not need my 6920 or DDM4v2.  I mostly shoot my M6A2 10.5 but I want a better mousetrap. 

Thanks for the help.


Original Post

Some will disagree, but I think assembling an AR, upper and lower, can be simpler and faster than assembling a plastic model.  The devil is in the details.  First and foremost, quality components and quality tools.  This is the danger when people are looking to save money v. doing it themselves to get something not available from a factory.  There are lot of differences between quality parts and those that appear to be the same, but aren't.  The materials used.  Heat treating where applicable.  Tolerances and how close to spec.  Testing to make sure everything is good.  The same is true when it comes to tools.  Do wrenches slip or fit properly.  Punches that bend.  Quality components and tools make it less likely that you are going to difficulties during assembly.  Which brings to instructions, training, skill, experience, etc.  A factory assembly is likely done by someone who has done hundreds of assemblies and is likely checked by others with even more experience.   For those operations that require 3 hands, they've got the tools and equipment that provide that 3rd hand.  The more eyes, the more likely that errors will be detected.  When you do it, yours are the only eyes.  Experience also helps a lot to know what is right, what is the likely cause when it is wrong, and what to fix.  Do your research on how to assemble correctly.  Torque settings, where to use locktite and where not.  Anti-seize compound on the receiver extension and barrel nut threads, etc.  The right order is also important.  And a cat to spot where springs and pins go when stuff flies.

I've used Aero parts and I think their quality is good.  The only negative I had was sight alignment on one of their upper and rail sets.  I'm considering using some Aero parts for my next build as well.  Your other producers are also known for their quality. 



Swear allegiance to the flag Whatever flag they offer

Never hint at what you really feel

Teach the children quietly For some day sons and daughters

Will rise up and fight while we stood still


Joined:  2/24/2003                          Location:  Nevada, USA

Last gun I put together had an Aero upper/lower, whatever the forged ones that look more like billet ones are called.  The first upper had the threads mangled by where ejection port door pin goes in.  The second upper had a messed up tolerance and the ejection port door wouldn’t close.  Third was fine.  Customer service was good and cover return shipping and was fast.  Past that no real tolerance or build issues.  Front of receiver was pretty square.

I’ll be interested in how that 11.5” barrel performs for you.  I shot my last one out and will be looking a replacement when I get around to rebuilding it.

Thanks, I see they are well thought of and like always since I do not need a all black rifle, they have cerekote things,  I was looking at other things like replacing a barrel at first but figured out selling a complete upper is easier than selling a barrel that I am not going to use. 

Building AR's is a very subjective thing.  I think it's been pretty well covered so I'll just say ditto to the above remarks.  Although I will also add that some guys doing it at home make stuff just as good, if not better than some factory models.  I don't care how many a company may put out, it doesn't mean they're all good;  you may have got one from the new hire or a guy rushing the job on a Friday.  And it some how skipped through QC.  But parts quality is definitely an issue.  I wish somebody would put out a "Kuhnhausen" style book on the AR.  Without mic'ing known quality parts it's damn-near impossible to tell some times.  

My personal preference for a go-to vendor has been "Right To Bear Arms and Supply".  Vet owned and operated, with several good brands to choose from, and usually really good prices.  

On tools, I think it's definitely worth it to tool up, although you may want to go in with several mates.  Especially to get the bbl nut torque right.  And a few other things, all discussed before.

The cool thing is parts have been so ridiculously cheap lately that you can afford to fuck up and then get it right.  So it's a lot easier to experiment with new brands right now.          

"Pacifism is a shifty doctrine where a person claims all the benefits of the body politic, without any of the responsibilities, and then claims a halo for their dishonesty." Heinlein

The hard part to building an AR is not knowing what to do, but knowing when something isn't right and how to fix it.  Grabbing the BFH and hitting it harder is rarely the answer.

Just remember:

"Building an AR is a bit like love or a fart...If you find that you're having to force it, it's going to turn out really shitty."

"Pain, we endure...faulty weaponry, we do not."

DLEHR beat me to it, and I agree fully. Just finished an upper built around a BCM "blemished/demo" part as mentioned above. I could not find any evidence of either any nicks, scratches, or prior assembly on mine, either. Had to heat the upper receiver pretty good to get the barrel to fit, but once in, it is like it whole thing is one solid piece before installing the barrel nut. Everything else went on straight and true, also. 

As a quality for the price proposition, I think this is a hard deal to beat.

 This is going on an Aero lower with the screw to adjust out the slop between the upper and lower receiver. Looking forward to seeing how accurate this will be.


The last upper I put together was a Noveske upper, Larue's pencil profile barrel, DD gas block & BCG, Midwest MLOK forearm, and an A2 flash hider. 

After a few years of armorer schools and working on office weapons, plus other influences, I had an idea of where I wanted to go and what components to get there. A delay popped up when I needed the jig and drill bit blocks to dimple the barrel for the gas block. 

Regarding the upper receiver, what I look for is fitment between barrel receiver -> barrel receiver extension. BCM blemished upper receivers are my go to. 

I have only tried 3 various other manufacturers (including 1 Aero AR15 stripped receiver and another Aero LR stripped receiver...) and the fitment of these to the various barrels they’ve been mated with have yielded less accurate rifles.  I won’t mention the other variables we could attribute the accuracy results, as well as all the other details.   My point is - the relationship between the barrel extension and receiver is very important, and unless you want to experiment with various methods to bed the receiver extension I would get a BCM stripped upper receiver every time unless I find something with a tighter, beefier, better fit for most barrels on the market. 

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