Jump to content
308AR.com Community
  • Visit Aero Precision
  • Visit Brownells
  • Visit EuroOptic
  • Visit Site
  • Visit Beachin Tactical
  • Visit Rainier Arms
  • Visit Ballistic Advantage
  • Visit Palmetto State Armory
  • Visit Cabelas
  • Visit Sportsmans Guide

Ar-10 Platform Build


bmoney9

Recommended Posts

Hi All,

It's been a long time since I've been around and wanted to get some insight parts. I bought a Matrix Arms AR-10 platform receiver (not dpms platform) set years ago and it's finally time to finish the build. What do you all recommend in the 16" barrel length for the rifle? I've seen Faxon, BA, and Criterion barrels recommended but not sure which way to go. Won't be hunting with this rifle but will look to shoot longer distances.

I've also looked at getting a LaRue tOBR barrel but I'm not feeling confident about the fitment into the Matrix Arms upper as I have seen a lot of their parts are proprietary. Right now I have the lower finished so looking to just complete the upper with the receiver I have. I also have KAK industries double ejector 308 BCG but can't remember if that will be compatible with this build. Though, I do believe so.

Anyone build one of these lately? Share your experience if you'd like.

 

Link to comment
Share on other sites

2 minutes ago, Robocop1051 said:

@98Z5V is a big buff on these. 
 

Tom, @bmoney9 is a personal friend. She’s some Gorilla wisdom. 

Great Sweet Baby Jesus - been here since 2014?!   I'll dig into it, brother. 

As far as barrels fitting into receivers, that's standardized across the industry, and barrel extensions (on barrels) all have the same O.D.  Or very, very damn close, and we're talking "needing a micrometer" to tell any difference.  Any barrel is gonna work in any upper (Not DPMS G II or any of that PSA "small frame LARGE AR stuff). 

For the standard .308AR, pick a barrel, pick your receivers - it's gonna work.  Matrix Aerospace is solid. The receivers are great, there are no flaws, and they work.  BA, Faxon, and Criterion are all great barrel manufacturers, so that will come down to the features that you want in that particular IDEA of what you want/need in a barrel.  Flutes?  Certain profile?  Certain material?  That kind of stuff.  You toss an idea out here @bmoney9, on what you're looking for on that particular barrel profile, and we can narrow that all down.  I've been on one hell of a BA kick lately - because they have the specific profile that I needed/wanted - and the material, and twist rate - and those damn things are accurate.  As Fuk.  To this day, though, my Kreiger-Criterion 10-year-old .308 Win barrel is the best barrel I've ever had.  And, I love the Faxon barrels that I have. 

You just can't lose, with any of those three companies.  You wanna go distance with a 16" .308 Win barrel?  It's easy.  Just need to know what you're looking for in that specific barrel.   :thumbup:

Link to comment
Share on other sites

Thanks @98Z5V got busy with other hobbies over the weekend brewing some beer but now that I've sat down I'd like to shoot between 600-800 yards using a 1:10 or 11 twist rate with a heavier bullet. Nitride would be the material I'm after and it looks like Criterion has quite a few barrels in stock compared to Faxon. I see Faxon only has a pencil profile barrel in stock.

I've only ever shot 16" sized barrels as well and don't see the reason to go any longer.

I'll keep looking around for a barrel and hopefully the BCG I have will headspace correctly with it.

 

Link to comment
Share on other sites

A 16" barrel will do 600 yards very well, and it'll do 800 yards with regularity - and accurately.  Go with a 1:10" twist, for sure.  The 11" twist will run 175s well, but that's right around it's limit.  You ever decide to go heavier, and you'll need that 10" twist.  Example:  Had some 195s laying around for 300 Win Mag loads, but I went with 225s in that gun.  For giggles, let's load up some test rounds with these 195s into the .308 Win cases...   :laffs:  They did GREAT at distance!!!  

Don't discount 18" barrels, either, though.  Criterion has one badass 18.5" .308 Win barrel that they make for Fulton Armory.  I think Criterion still provides it for FA, but they also sell it themselves.  That barrel right there is the baddest .308 Win barrel that I own. 

Brewing beer, huh?  You busy this Fall, by chance?...   :popcorn:

Link to comment
Share on other sites

Ok - I'll look more into 18" barrels. Is there much gained from longer lengths? I've read not much but what's your take on it?

I'll be starting to reload 308 so interested in lengths out to 1000 yards but probably not for this build. I have different lower receiver that will need build as well. haha.

I'm always trying to keep the kegs full for the random parties or family get togethers.

Link to comment
Share on other sites

  • 3 weeks later...
On 6/24/2020 at 8:28 PM, bmoney9 said:

Ok - I'll look more into 18" barrels. Is there much gained from longer lengths? I've read not much but what's your take on it?

I'll be starting to reload 308 so interested in lengths out to 1000 yards but probably not for this build. I have different lower receiver that will need build as well. haha.

I'm always trying to keep the kegs full for the random parties or family get togethers.

Many people quote 75-150 fps per inch when it comes to barrel length. The higher end is more for say 22-250 or other similar calibers where muzzle pressure is higher. 98 is way more of a long ranger than I am but to me the key thing is when the bullet velocity goes trans sonic. I have been an exterior ballistics devotee since my teen age years so this is kinda old hat :-).

These kind of tests here are great.

http://bulletin.accurateshooter.com/2015/06/308-win-barrel-cut-down-test-velocity-vs-barrel-length/

There are a ton of external ballistics links and apps, I kind of like this one, but to me what is important is to find one and use it enough to get familiar. I used the 168 grain load listed in the ballistics by the inch, probably few would choose 168 for 1k yards but it just gives us a quick idea what might be going on. Just guessing at the graph I knocked off 100fps for the 16". vs 18".

Another issue is that many 16" barrels use mid length gas, and quite a few of the 18" use rifle gas tube location. IMHO overall if we use the optics to support 1k work adding 2" of barrel from 16 to 18 would not be bothersome at all really. 

 

c0YY81L.png

jncGHUC.png

 

Edited by willbird
Link to comment
Share on other sites

On 6/24/2020 at 5:28 PM, bmoney9 said:

Ok - I'll look more into 18" barrels. Is there much gained from longer lengths? I've read not much but what's your take on it?

I'll be starting to reload 308 so interested in lengths out to 1000 yards but probably not for this build. I have different lower receiver that will need build as well. haha.

I'm always trying to keep the kegs full for the random parties or family get togethers.

There isn't much loss, per inch, and Bill hit's that below vvv...

10 hours ago, willbird said:

Definitely one of my favorite article to quote, when someone starts talking about velocity loss because I bring out a gun that's short...   :thumbup::lmao:

@bmoney9 - can you SHOOT a 16" gun to 1k yards?  Yep, if it's a good gun (barrel and trigger mainly, and ammo, of utmost importance).  The whole gun needs to perform well, including balanced gas and recoil systems, though.  No fancy parts required, just a solid-built gun.

Is it easier on you shooting an 18" gun to 1k yards?  It is.  It's more predictable, and it doesn't taper off towards that transonic barrier as quickly as a 16" would - and that's the key in the whole thing.  As long as your projectile is supersonic - you can plot where that shot is going to go, every single time.

If I have an accurate 16" gas gun, and I'm shooting it against an accurate 20" bolt gun - I just need to know the verified drop at different distances, for both.  I might have to dial more for the 16", than I would the 20" - but an accurate gun is still an accurate gun.    :thumbup:

If 1k yards is really the goal, doing an 18" gun will be easier for you to "see results with, faster..."  - than building a 16" gun.  There's alot of trial and error in making short guns accurate at significant distance.  Test it, run it longer next time, gather your data, shoot it longer the next time...  You can shorten that process if you have other guns in the same caliber, with longer barrels, though.  With an 18" Grendel, I knew what my drop was at 850 yards.  Then, I tried the 12.5" Grendel at that distance - I just added more drop, and had a good spotter calling dirt splash for me - it didn't take long to get that thing in steel at 850 yards.  The difference was 18" gun went 8.5 mils of drop at 850, 12.5" gun need 10.6 mils of drop to hit 850. Little trial and error to come up with it - but I already had a shortcut because of the known dope on the longer-barreled gun in the same caliber, same load. 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...