Mega MA-TEN build: now in 6.5 Creedmoor AND .308

vmpglenn

Sergeant
Full Member
Minuteman
Dec 4, 2004
393
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Fitchburg, WI
I just finished building a .308 gas gun on a brand-new Mega MA-TEN upper and lower set.

The barrel is a Noveske N6 1:10 polygonal twist 21" stainless tube, and I'm using an Armalite AR10 BCG. LPK is all AR-15 -- the AR10 bolt catch won't even fit -- and I'm experimenting with a Wilson Combat TTU two-stage drop-in trigger module. The handguard is a JP/VTAC LR308 rifle-length unit.

Scope is my trust NF F1 mounted in a Larue LT112 mount with 20MOA built-in slope. I'm deciding between this mount, which gives me a very heads-up cheekweld, or the NF 1.375" Unimount.

I have a heavy AR10-type shortened carbine buffer mated to a Tubbs extended flat-wire action spring. I'm going to see if the rifle length gas system mated to this spring and buffer will delay unlocking long enough to mitigate primer issues with the Hornady Superformance 178gr rounds.

<span style="font-weight: bold">EDITED TO ADD: Now in 6.5 Creedmoor!</span>

Yes, I have over 4,000 rounds of .308 ammo... and I built a 6.5 Creedmore rifle.
crazy.gif
Even better, I don't even own a .308 anymore.

<span style="font-weight: bold">The Build</span>
As has been reported by others, the MA-TEN upper/lower kit is very well made. I won't go into that, other than to say the set is well worth the asking price.

I ran into several challenges building my 6.5 Creedmoor rifle. The first was the unique shape of the MA-TEN upper: it would not fit into on onto any of the .308 action blocks I had on hand. I ended up Dremeling a Bushmaster action block to fit around the billet shaping of the upper.

I also found the barrel extension on my Noveske barrel fit extremely tightly into the upper receiver. I had to tap the barrel into the upper, using plenty of Slip 2000 EWL. I guess this is a good thing from a stability point of view... Anyway, the extension did slot into place with no real drama - just a little extra effort.

Everything else went smoothly. The lower takes all AR-15 parts, including the magazine release and bolt catch. The bolt catch retainer is threaded, so this part goes in very easily. There is also a threaded insert to keep the rear takedown pin retaining spring in the receiver, so a Magpul MIAD or MOE goes on with no modifications. My MOE also fits nearly flush against the bottom of the receiver; there isn't the usual gap between the back of the grip and the lower.

So along with the Noveske 20" 6.5 Creedmoor 1:8 poly stainless barrel and Armalite AR10 BCG, I ended up using a Stag LPK I had in reserve, a Geissele DMR two stage trigger (the Wilson TTU would not reset correctly for some reason), an Armalite milspec carbine receiver extension, a Slash-type heavy buffer, and Tubbs flat wire action spring. The stock itself is a Magpul ACS, which balances the rifle nicely and provides an excellent platform for shooting prone. And the handguard is a JP/VTAC rifle length unit for the LR308 with the full length top rail and 4" bottom rail. The bottom rail's purpose is to interface with a DCLW tripod with DLOC attachment system.

The muzzle device is a Vltor VC-301, and the scope is a Nightforce F1 in a Nightforce Unimount with 20MOA slope built in. I decided to skip the front and rear BUIS, since this rifle will be shot only in the precision role. If I do stick anything else on the top rails, it'll be an AN/PVS-24 or similar.

The rifle weighs 12lb 7oz empty. Here's how it turned out:

maten65_1000.jpg

maten65_angled_1000.jpg


<span style="font-weight: bold">The Range</span>
I've only had the rifle at the range once, to zero the scope and chrono the Hornady 129gr SST Superformance factory load.

With the LR20 mags, the rifle functioned flawlessly. Recoil was very tame, helped in no small part by the heavy buffer and Tubbs action spring. The Geissele trigger, though originally meant for an AR15, never failed to light the Hornady ammo's primers.

The 129gr SST Superformance ammo averaged 2780fps corrected to the muzzle, making this load good for about 1100 yards. The 140gr Amax loads should go past 1200 with no problems.

Accuracy was a little under MOA, but I was not really shooting for groups. I'm much more interested how this rifle does past 600 yards, so that's next on the list. I'm looking forward to building confidence in this rig.

<span style="font-weight: bold">ETA: My 6.5 CM upper now has a .308 sibling...</span>

I had a 21" Noveske .308 N6 barrel lying around (along with some .308 ammo, of course), so I decided to have Adco cut it to 18.5" and GunKote it flat black. I left the gas port alone, but surprisingly the rifle still feels a bit overgassed. I'm curious to try some lower powered military surplus .308 to see if the gun will cycle - Noveske's ammo guidance nonwithstanding...

Not the greatest photo, but the whole upper turned out just great:

maten_308_range02.jpg


The scope is a SWFA Super Sniper 3-9x42 FFP mil/mil in NF low rings and a Badger Ordnance 22MOA AR riser, which is just perfect for the 0-600 yards I'll be shooting the .308 upper. For longer range stuff I'll just swap over to my 6.5 Creedmoor upper and NF F1 scope.

Here's the tail end of my zeroing session with the Super Sniper and .308 upper shooting Hornady 168gr Amax factory ammo (100 yards):

maten308zero.jpg


The N6 barrel is much more accurate than I am.

I'm still investigating bolt catch options for the lower, but I'm extremely happy with both uppers.
 
Re: Mega MA-TEN build: ready to go

Dude, that rifle is awesome. It seems there are very few pictures of 20"+ .308 ARs out there with collapsible stocks. I was always scared to do that in fear of it looking odd but it seems to fit well.

Let us know how she shoots!
 
Re: Mega MA-TEN build: ready to go

That is amazing the platform uses both Ar-10 style and DPMS style barrels. Freaking sweet you are able to utilize noveske.

Funny you posted this, I just made a thread about the JP/VTAC handguard on an ar308.
How is it? Does it feel pretty sturdy/heavy?
Was it a pain in the ass to install? And does the top of the rail line up with the upper receiver?

Thanks, and SWEET build.
 
Re: Mega MA-TEN build: ready to go

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: gunsmithcat</div><div class="ubbcode-body">That is amazing the platform uses both Ar-10 style and DPMS style barrels. Freaking sweet you are able to utilize noveske.

Funny you posted this, I just made a thread about the JP/VTAC handguard on an ar308.
How is it? Does it feel pretty sturdy/heavy?
Was it a pain in the ass to install? And does the top of the rail line up with the upper receiver?

Thanks, and SWEET build. </div></div>

The JP handguard seems solid so far, but I haven't had a chance to wring it out. I used Rocksett and an appropriately sized drill bit to hold the outer nut in place while it tightened the inner barrel nut. This seemed to work fine, and I don't have to worry about the handguard being permanently Loctite-bound to the upper. The weight is a non-issue; it's light.

The top rail is about 1/16" lower than the flattop upper, but this is no big deal to me as I don't expect to be using irons on this rifle. The rail is there for the sling mount and - if I ever decide to go nuts - a PVS-22 or similar nightvision device.
 
Re: Mega MA-TEN build: ready to go

Well...

Just when I thought this rifle was done, I found myself completely unable to resist the pull of a Noveske N6 20" barrel in 6.5 Creedmoor.

New pics and a shooting report coming shortly...
 
Re: Mega MA-TEN build: ready to go

The rifle with no scope, no mag, weighs about 9.5 lbs. WIth the NF F1 and a loaded mag you're near 14 lbs. It's not a walking around gun, that's for sure.

The build quality of the upper and lower is simply stellar -- Mega builds these uppers and lowers as matched sets, so they fit together perfectly.

Of course, the real proof will be in how these components stand up to lots of shooting, whether everything is "in spec" to allow the use of a wide range of AR15 parts...
 
Re: Mega MA-TEN build: ready to go

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Postal0311</div><div class="ubbcode-body">How do you like the ACS stock on the .308? How do you think it compares to the SOPMOD? </div></div>

The ACS is much better for shooting in the prone position. In terms of cheekweld and comfort, they feel about the same. IMHO the ACS also balances out a long rifle better than the SOPMOD.
 
Re: Mega MA-TEN build: ready to go

I like it a lot. Never seen the Larue LT112 before.

Vltor VC-301 looks cool on it. I'm really surprised that all(but a few) of the the Armalite and DPMS parts are interchangeable.

Coolest part is to see Armalite pattern bbls and carriers being used with the KAC/DPMS mags.
 
Re: Mega MA-TEN build: ready to go

Well... In the OP I do mention the Hornady 129gr SST Superformance loads going 2780fps. No pressure signs, fed and extracted fine with my heavy AR10-type buffer and Tubbs extended flat wire action spring.

If I can find some of the 140gr Amax ammo I'll chrono that too!
 
Re: Mega MA-TEN build: ready to go

I believe Midway has that 140 gr amax load, Ive been waiting for LMT to come out with their 260 barrel for my MWS, this has me thinking,,,I figure about 2k plus optics for this build
 
Re: Mega MA-TEN build: now in 6.5 Creedmoor AND .308

Would you have a detailed pic of the threaded bolt catch pin? I'm milling out my own lower and am trying to incorporate a few different things that just make sense that the original Armalite pattern doesn't use, and was just curious how Mega does it. I already plan on putting the set screw in for the rear takedown pin detent, and probably the upper tension screw as well.

Thanks

nice looking rifle BTW!