Why is building an AR10 so damn complicated?

[JohnnyBfromAZ]

So, here's a little bit about my current woes:

 I've been wanting to build an AR10 SBR (possibly Form 2 it into a Post 86 MG) for awhile now. I wanted the rifle to look pretty close to a scaled up version of the MK18, with a no frills, forged upper and lower receiver, a DD 762 lite 12" rail, and maybe like a B5 Bravo or SOPMOD stock. I had some criteria that I wanted to accomplish, which is what is making this build so difficult to complete.

1. Armalite AR10 Style upper and lower. I think the radius of the DPMS style is hideous and rarely match up unless it is a well made set.

2. Slick upper: I have never been an advocate for a forward assist on AR type rifles, and even more so on 7.62 variants. If a 308 round doesn't want to go into battery for some reason, the last thing you should do is force it.

3. Armalite or DPMS height upper. I found my unicorn rail finally, so it needs to match up on height.

4. Needs to take SR/DPMS mags. Obviously; If i wanted hacked up and repurposed mags, I would buy a SCAR 17(JK, no I wouldn't)

5. I need a 13.5" barrel, chambered in 7.62x51, with a mid length gas port.

6. MAYBE a F/A BCG since it might end up as a posty MG.

So, the problem is that most of these parts with these characteristics are either Armalite only, or DPMS only, which is infuriating. I found out about Genesis CNC, and it seemed like their Upper and 80% lower would be the ticket, but I can't tell if they're even in business still. I've called and emailed to no response. I could try to source a KAC upper and lower, but they are priced ridiculously, and I'm not that big of a fan. I would just get an Armalite SPR Mod 2 AR10A upper and lower, but Armalite is out of business while they are moving(I've been to their facility here in Phx, and I don't know what the holdup is). Plus, they insist on putting forward assists on their uppers. So, if anybody knows any companies that make the parts I need or can help point me in the right direction, I sure would appreciate it!

[98Z5V]

3 hours ago, JohnnyBfromAZ said:

a DD 762 lite 12" rail,

3. Armalite or DPMS height upper. I found my unicorn rail finally, so it needs to match up on height.

4. Needs to take SR/DPMS mags. Obviously; If i wanted hacked up and repurposed mags, I would buy a SCAR 17(JK, no I wouldn't)

5. I need a 13.5" barrel, chambered in 7.62x51, with a mid length gas port.

 

Since the rail is discontinued, and you found one - what's it threaded for?  Armalite or DPMS?  It's one or the other.  That right there drives everything else on your build right now.

Sounds like you want to build this:

That's a 13.5" barrel, midlength gas.

[JohnnyBfromAZ]

So, as far as i can figure, you can put this rail on either. It came with a 16tpi and a 18tpi barrel nut, and the rail is at the Armalite/DPMS high .210 height. That 13.5" armalite barrel might be my only option as far as i can see, which means now i have to go the AR10 route- which is going to be harder to find the parts i want. Hence my interest in the Genesis upper and lower, but i havent seen anything from them lately.

[JohnnyBfromAZ]

That picture is interesting. That appears to be the Armalite 13.5" mid gas barrel that is available on their website. What puzzles me is the fact that it can go on the M5E1 upper, which i thought could only take DPMS barrel extensions, so what gives?

[98Z5V]

8 hours ago, JohnnyBfromAZ said:

That picture is interesting. That appears to be the Armalite 13.5" mid gas barrel that is available on their website. What puzzles me is the fact that it can go on the M5E1 upper, which i thought could only take DPMS barrel extensions, so what gives?

That is the Armalite 13.5" barrel on their website.  Barrel extension external dimensions are the same.  Note that the barrel listed on their website is NOT 1:8" twist, and that's a typo on their website. It IS 1:10" twist. 

That rifle above is all Aero Precision upper/lower/rail (DPMS pattern parts) with a complete Armalite AR-10 operating system and recoil system.  Armalite barrel, brake, BCG, receiver extension, buffer, buffer spring.  Runs like a beast, too.

That rail you have would work perfectly on the AP upper receiver.

Edited June 30, 2018 by 98Z5V

[98Z5V]

Finally finished the last thing I needed to on that rifle. Received the AP 30mm mount a few weeks ago, and just painted it last weekend.  That was the last thing it needed.

[JohnnyBfromAZ]

It looks super sick dude. I'm thinking now, in lieu of getting an armalite AR10A upper/lower, of going with either the matrix arms set or the M5. The position of the FA on the Matrix is bothersome to me, but the curved receiver of the M5 just doesn't do it for me. Can't decide the lesser of two evils. Maybe I'll see if i can't scare up a slick armalite flattop upper here pretty soon. Now, i know what the answer is before i ask it, but I'll ask anyway- can i use an Armalite bolt in a DPMS carrier? The Lantac heavy EBCG caught my eye, and i thought about going the tuned heavy mass route, rather than the light mass JP route. It looks like the Lantac has  DPMS bolt dimensions though. I've actually read that some people managed to stuff a DPMS bolt in an Armalite carrier and it headspaced okay.

[survivalshop]

  There are slight differences between the two BCG's , dimension & spec's wise , we have a thread on it around here some where . Now, can you swap BCG components & still get a safe Head Space , well thats something else & its your call.

  The only real advantage with the AR 10 Bolt to the DPMS/SR25, is the Spring loaded Firing Pin , if you can call that a advantage , there are reasons floating Firing Pins are used in Battle rifles .

And its really not too difficult to Build a large Frame AR , just stick with one platform or the other & it should work out just fine , its when some start mixing & matching different platforms or in some cases , proprietary components from some manufacturers , that cause issues . Like mixing different manufacturers upper & Lower Receivers .

Edited July 1, 2018 by survivalshop

[dprice38444]

https://tacconusa.com/tac-con-in-action/

give this trigger group a look. cheaper than messing with nfa

[Merle]

I know I'm a little late to the party but I'm about to start assembling a rifle using a Centurion Arms SR-25 compatible upper and lower receiver set. It has the KAC/Armalite angled cut and is sans FA. It sounds like its right up the OPs alley. I had to wait a while for these to come back in stock and it lloks like as of now they still have them. 

[98Z5V]

3 hours ago, Merle said:

I know I'm a little late to the party but I'm about to start assembling a rifle using a Centurion Arms SR-25 compatible upper and lower receiver set. It has the KAC/Armalite angled cut and is sans FA. It sounds like its right up the OPs alley. I had to wait a while for these to come back in stock and it lloks like as of now they still have them. 

I've been WAITING for this news to drop, brother!!!  

[Merle]

16 minutes ago, 98Z5V said:

I've been WAITING for this news to drop, brother!!!  

Hell yea! I'll probably start a thread once I get all my parts together. Still trying to decide on a few things like which barrel to go with. Too bad I gave some bearded fella all my 308 brass. Ha! 

[98Z5V]

7 minutes ago, Merle said:

Hell yea! I'll probably start a thread once I get all my parts together. Still trying to decide on a few things like which barrel to go with. Too bad I gave some bearded fella all my 308 brass. Ha! 

I still have it in the bag!!!  Christmas is coming, and I can "re-gift" it!!!