Help finding or bulding an AR10 Armalite upper

[edteach]

I bought an AR10 Armalite lower a few years back and then all the stuff that ran up gun prices happened. I waited to see if prices would come down and they seem to be now. I need to build or buy an Armalite upper. I see Stag has them upper with BCG for 389 and would still need barrel, barrel nut, gas tube, hand guards. not sure what else I would need. Thanks for any help. I do have the Armalite not the DPMS lower.

[shooterrex]

You might check Diamondback. I think their uppers match up with Armalite.

[edteach]

I did they are out of stock of everything I need. Stag has in stock products.

[Armed Eye Doc]

Diamondback has stripped uppers in stock at the moment.  They also have complete uppers available.

https://diamondbackfirearms.com/shop/upper-308-stripped-upper-receiver-2-5/

[shooterrex]

You can call Armalite. They seem to be able to find parts if you call them most of the time.

[edteach]

I ended up going with Stag, they were the only ones who had stock. I bought the Stag 10 Tactical 16" Upper with Nitride Barrel in .308 - FDE - Left-Handed a LH BCG and Charging handle. I think I may have gotten one of the last ones as its not on their site anymore. Not sure how long things are BO now. But most places are out of stock on what I was looking for or they wanted 1800 for an upper.

[jtallen83]

13 hours ago, edteach said:

I ended up going with Stag,

Curious how you determined it was compatible with the Armalite lower? Is the lower a B model Armalite with proprietary mags or the P-mag compatible A model?

[DNP]

Looks like the Armalite cut on those…keep us posted if that mates up well. Claims everything else about it is DPMS compatible. Worst case a Stag lower solves the problem and you have the Armalite for another build. Hopefully it works out great and you’ve got a functional rifle up and running soon. Looking forward to the range report. 

[edteach]

I believe it would be the A model. It takes the DPMS mags. I talked to a tech at Stag and he said that they recommend their lowers, but than said that it should work on my lower as all their AR10s are Armalite compatible.

[DNP]

We typically try to keep upper and lower receivers of the same make to have less headaches. Having no real spec for the big frames means everyone has something just a little bit different than the others. Can’t always go that way though and plenty have mixed and matched before. Stag makes decent stuff, so I’m optimistic all will fine. The proof is in the final product. Check out all the other fun issues folks have with their builds. Make sure your recoil system is correct and check the size of the gas port in your barrel before final assembly. There’s plenty of threads around here solving function problems that will give you an idea of what to look for. 

[edteach]

This is the lower I built and am hoping to fit the Stag upper to.

[DNP]

What buffer do you have in it?  Make sure it’s 5.4 oz +/- and that it’s the right size for your tube depth. 

[edteach]

I believe I have an AR15 Buffer in the tube. Its 4oz. So thanks for bringing it to my attention.

[edteach]

This buffer seems to be running around the weigh I find many AR10s, I think I will run the gun to see how it works. If it feels at all funny I will go to a heavier spring and buffer.

[Rsquared]

5 hours ago, edteach said:

 

Whoa. I don't think that I've seen one of those scales since I was a MUCH younger guy.

Outstanding.

[98Z5V]

1 hour ago, edteach said:

This buffer seems to be running around the weigh I find many AR10s, I think I will run the gun to see how it works. If it feels at all funny I will go to a heavier spring and buffer.

You'll need more than that.  Don't even start with it, don't waste your time.

Or, do what you want.  We'll be here... 

[DNP]

I question the accuracy of the scale. You feel that one is pretty well calibrated?  
 

The reason you see other guns running 3.8oz buffers is because they’ve tried to cheap out. They undersize the gas port to make up for the lighter buffer…and then people come onto the internet to find out why the gun jams regularly. 99.99% of the time it’s a bad recoil system and/or an undersized gas port. Get the right buffer and spring in there, get the hole right, you’ll have a rifle that eats any ammo you feed it. 

[edteach]

I checked my scale by putting a known test weigh that came with my digital scale for powder, It shows 3.52 oz. I put that weight on the scale and it shows 3 oz. So if anything my buffer is heavier than 3.8 oz. I would put it on my digital scale but its over what it will weigh. I am going to give this a try and if it does not function well I will trade them out.

Edited April 17, 2022 by edteach

[98Z5V]

1 hour ago, edteach said:

 So if anything my buffer is heavier than 3.8 oz.

No it's not.  The heaviest you can make a 2.500" buffer with an aluminum body is 3.8oz, and that's with 2 tungsten weights inside it (because that's all that fit inside there).

It's a 3.8oz buffer.

The only way to make a 2.500" buffer heavier, is by changing the material the body is made of.  Stainless steel bodies with 2 tungsten weights will get it to 5.3oz~5.6oz.  Depends on how thick the rim is.  You'll be getting rid of that 3.8oz buffer, because it's not going to work properly.  You'll also need to check the length of your gas tube, and your gas port diameter.

Edited April 17, 2022 by 98Z5V

[98Z5V]

@edteach, there's a very specific reason that Armalite uses 3.250" buffers that are 5.4oz, in carbine receiver extensions that are 7 5/8" internal depth, with their EA1095 recoil spring.  In ALL their factory AR-10 Carbine Recoil System guns.  Because it works, and doesn't fail, and doesn't compromise any other part of the gas system.

Read this, when you have the time:

 

[98Z5V]

@edteach, you can buy this buffer for $22 from DSG Arms.  It's stainless steel body and 2 steel weights inside, and it weighs 3.8oz.  You can get that for $22, take it apart, take your buffer that you have apart, and put YOUR tungsten weights inside this DSG stainless buffer body, and hit 5.3oz.  That's close enough.  I've done it, tried it, and it works, and it's running inside my .260 Rem gun right now, and won't be coming out.

This is the cheapest way you can solve this issue.  You WILL NEED a Sprinco Orange spring for a recoil spring, with this setup.  Nothing else will work.  They run around $20.

https://dsgarms.com/lower-receiver-parts-dsg-4201-0021

Edited April 17, 2022 by 98Z5V

[edteach]

Thanks for all the help. I measured my tube and its 7.25 inches outside measurements, so if I need a 7 and 5/8s inside tube I will need to repalce the tube, buffer and spring. Here is a set up from Stag for my upper from stag but under specs it does not tell me much. https://www.stagarms.com/stag-10-carbine-receiver-extension-kit-stag300732.html

[shooterrex]

This works as long as your gas system is correct.

https://www.armalite.com/SACItem.aspx?Item=AR10REKIT01&ReturnURL=/Armalite/Product-Category/AR10-Parts-Accessories&Category=4eeff98b-d9a6-40fd-be6b-ab2e44ec1080

[edteach]

I did take my buffer apart and the internals are either balls or rods and are pressed in not movable so that fix is out.

[98Z5V]

11 minutes ago, edteach said:

Thanks for all the help. I measured my tube and its 7.25 inches outside measurements, so if I need a 7 and 5/8s inside tube I will need to repalce the tube, buffer and spring. Here is a set up from Stag for my upper from stag but under specs it does not tell me much. https://www.stagarms.com/stag-10-carbine-receiver-extension-kit-stag300732.html

That Stag spring is excessively stiff.  I've seen them at the gun shop, tested them on the range, and had to change them out - for my gun dealer working on a customer's gun.  Just get the Armalite kit, or do what I said before. Rebuild the buffer from the part I listed from DSG Arms, and use a Sprinco Orange Spring.  If you do this, the internal depth of your receiver extension needs to be 7.000" INTERNAL.

Overall length on a receiver extension doesn't mean a hill of beans.  INTERNAL DEPTH of the receiver extension is what matters.  How deep is that extension?  That's all that counts.