View Full Version : Help me build a 6.8
Okay, I have a LaRue OSR on order, but now after spending (too much) time on this board, I am starting to second guess the direction I wanted to go in. I have become enthralled by the 6.8spc, and leaning heavily towards building one, so this whole premise is somewhat hypothetical. What I have come up with so far, and it's not much yet, is an AR Performance upper (MK68 SAM-R 18") with their new, soon-to-be-released long-stroke piston system, and a lower from either LaRue or LMT. The basic purpose of this rifle will be to punch paper, feral pigs, and the occasional zombie out to a couple hundred yards.
Based on your opinions, am I headed in a good direction so far?
If you are thinking about piston, why not go with an Robinson arms XCR? Nice 3 lug bolt that is tough and easy to clean. Their 1/11 twist barrel is due anytime now, though with 4 groves and specII chamber I don't get any pressure signs from SSA's "tactical" loads in my 1/10 twist barrel. You will get a 5 position gas adjust, full rails, as well as a rifle that can be used to bludgeon the zombies to death when you run out of ammo (and run again when you find some)...
Crenca, I guess I really don't have a good answer for you. I am hooked on the AR format, and other than basic specs, I don't know a whole lot about the XCR, or Robinson Armament in general.
diving dave
09-02-09, 10:10
You probably wont be sorry with AR Performance, very good customer service. I have a MK68, but its been here for about a week. No range report yet. But she looks sweet...:D
http://farm3.static.flickr.com/2542/3877859515_91a1e70c77.jpg
BLACK LION
09-02-09, 15:50
AHHHHHHH... there it is again...
Nice rig Dave...
To the OP
You cannot go wrong with Harrison... Your rig will be treated like a virgin princess and you can count it being a life long shooter for the purposes you stated.
He builds worhorses that will outshoot thier owners and he is very meticulous about the assembly of each one... if something is off, you wont get the rig till its squared away...
You also have the superbolt option , Carbo nitrided option as well....
Once he machines the piston I hope to be one of the first 6.8 rigs running one...
diving dave
09-02-09, 16:12
Hahaha, blacklion you and I seem to be running in the same cirlcles brother!:D
one of my buddies has a Bushy 6.8 and he installed a different muzzle brake and it was very pleasant to shoot.Nice caliber and very interesting .
benthughes
09-03-09, 03:43
Gas piston guns are all well and good ( well, not all.....) but if you're thinking about running a mid length gas system I don't think you need it unless you're running suppressed alot. I've got a LWRC and while I like it, compared to my DI guns, it's heavier, recoils more and just gives me extra parts to clean. It does keep things a cleaner though.
My 6.8 middy is DI and I couldn't be happier with it in that setup. You can buy or build a super DI upper with cash left over for ammo, a coke and a smile for what you give for a piston 6.8.
Thanks guys, appreciate all the info and opinions!
TXSUT
My thoughts on pistons are as follows, they are fine but not necessary unless your into supressed shooting etc.
Now, that said, I think the LMT 6.8 piston is good, and if thats the one your set on, I THINK you might want to wait until sometime after Janurary. I have a feeling they might update their specs to 1:11 with the SPC II chamber.
I am looking forward to seeing the ARPERF long stroke piston.
I have shot the ADDAX PISTON 6.8, the Barret REC 7 piston and the POF USA 68 piston, all shot well. I think any piston will work for your needs really.
Now, if your aok with a DI my suggestion for barrles for the build would be as follows in no real order.
Noveske
AR performance
Bison Armory
SOAD (Lothar Walthar's storefront coming soon)
WOA 6.8 barrels (again getting great reviews)
As far as the rest of the build, hogs and paper punching, you can go a variety of ways, I can give you my thoughts as of now on the topic:
I like the TROY EXTREME RAILS a lot right now, as well as the PRI tubes.
VTAC is also great for the money.
As for a muzzle device, the PWS FSC30 is a fantastic choice.
Stocks, thats personal preference really.
Trigger, I like the Gisselle Arms or AR GOLD. (you said paper punching, how accurate do you want to be?)
BLACK LION
09-03-09, 15:07
Gas piston guns are all well and good ( well, not all.....) but if you're thinking about running a mid length gas system I don't think you need it unless you're running suppressed alot. I've got a LWRC and while I like it, compared to my DI guns, it's heavier, recoils more and just gives me extra parts to clean. It does keep things a cleaner though.
My 6.8 middy is DI and I couldn't be happier with it in that setup. You can buy or build a super DI upper with cash left over for ammo, a coke and a smile for what you give for a piston 6.8.
+1 ....
I fondled the piston idea and am still fondling it to this day but what was quoted here is pretty spot on...
You shouldnt need a piston with a properly set up DI gun... If you go to the lengths to have it built by someone who has mastered smithing the AR platform... Basically, someone who knows how and is fully capable and willing to go above and beyond to build you a "lifer"....
Likewise... the break-in procedure is important to how your gun will run short and long term... I am a fan of fire lapping the barrel to remove whatever is left over from the assembly process which cuts fouling and other hinderances down to a miniscule amount... I have yet to have to "clean" my rig after almost 500 rds not to mention what was used during the break-in ...
I run a little Otis SF dry lube and a bore snake and thats it... I take out the bcg and inspect it for build up and it is squeaky clean...
Some people want it so they dont have to clean as much but that really doesnt make sense when you look at it...
I feel its a matter of who is building the rig taking extra steps that most wont...
I didnt just focus on the barrel but on the bolt and carrier group as well... My bcg was already assembled at WOA but when I sent it to TimW(now TitanAmory) he immediately saw room for improvement and went above and beyond to whats now thier standard offering in all their bcgs....
Unless you are firing thunderstorms of ammo in a short time and running a supressor you may never really see the benefits of the piston over a properly set up DI rig.... Most of us, including those in theater and those behind the gun every single day may never find themselves in a position to where they are abusing thier rig enough to need a piston...
I dont have select fire capability nor can I legally own a supressor... I also am not the type of shooter that fires to the extent that I could cook a slab of bacon on my rig...
I do see the merits of a piston and now that Harrison has his adjustable version coming out soon I plan on seeting up 1 of my 6.8 rigs as a piston... I do plan on running a suppressor once I move to a state that allows it... Not that I feel like I will be doing enough to warrant a piston but I would like the best of both worlds...
another vote for Harrison at AR15 (or Titan dependant upon your location)
I personally haven't had a problem with DI and I have put LOTS of rounds through my ARs without cleaning the gas tube
I love my 6.8 :)
http://img25.imageshack.us/img25/2386/reconcoker.jpg
"Now, that said, I think the LMT 6.8 piston is good, and if thats the one your set on, I THINK you might want to wait until sometime after Janurary. I have a feeling they might update their specs to 1:11 with the SPC II chamber. "
Cold,
I have a LMT piston in 5.56 but was told when I contacted them they had no plans to offer it in 6.8. Has that changed?
"Now, that said, I think the LMT 6.8 piston is good, and if thats the one your set on, I THINK you might want to wait until sometime after Janurary. I have a feeling they might update their specs to 1:11 with the SPC II chamber. "
Cold,
I have a LMT piston in 5.56 but was told when I contacted them they had no plans to offer it in 6.8. Has that changed?
Oh I just have a little feeling their 6.8 specs "might" change sometime after Jan 2010. Then again maybe nothing will happen.
LMT has said nothing to me and I have not asked them anything about it however, just some other things might change which well, just keep an eye out and we shall see.
I think 2010 is going to be a great year for the 6,8 :)
Oh I just have a little feeling their 6.8 specs "might" change sometime after Jan 2010. Then again maybe nothing will happen.
LMT has said nothing to me and I have not asked them anything about it however, just some other things might change which well, just keep an eye out and we shall see.
I think 2010 is going to be a great year for the 6,8 :)
That's good to hear. My SBR paperwork has the 6.8 listed and I've held off all these years on it. I do need to do the LMT route I think and do a short barrel in 5.56 and 6.8
That's good to hear. My SBR paperwork has the 6.8 listed and I've held off all these years on it. I do need to do the LMT route I think and do a short barrel in 5.56 and 6.8
I am with you, if LMT changes Im going to get one of their 6.8's until then its Noveske for me.
Like I said, I think 2010 will be a big year for the 6.8, or maybe not. Ill be posting from SHOT per usual with AR Variants news like I do over on ARF.
A bit of an update...I just got off the phone with AR Performance. Ordered the 6.8 Recon with 11" Troy Extreme rail and PWS FSC 30. :D Now I gotta figure out what lower to use...one of my Colts or get one dedicated for this upper.
Thanks again for everyone's help so far!
-Pete
BLACK LION
10-05-09, 17:48
A bit of an update...I just got off the phone with AR Performance. Ordered the 6.8 Recon with 11" Troy Extreme rail and PWS FSC 30. :D Now I gotta figure out what lower to use...one of my Colts or get one dedicated for this upper.
Thanks again for everyone's help so far!
-Pete
Keep up the hard work!!!
I am with you, if LMT changes Im going to get one of their 6.8's until then its Noveske for me.
Like I said, I think 2010 will be a big year for the 6.8, or maybe not. Ill be posting from SHOT per usual with AR Variants news like I do over on ARF.
I'll see how it goes, whether I wait and see or just go with it now. ARP was supposed to get back with me--never did
Mark,
While I cannot speak for ARP, I have communicated with him on several occasions, I know he is very busy, but he will get back to you. He might have simply overlooked it, intending to get back to you.
It has happened to us all at some point. I suggest you try contacting him again and see if you get a reply.
justin_247
10-06-09, 07:35
I was doing a thought experiment the other day and went a bit overboard and actually looked everything up that I wanted to do with a 6.8mm rifle. I decided I wanted to build a "battle carbine," if you will, that a hypothetical military force (preferably the U.S. military) could use if they bought an entirely new rifle from the ground up and here are the requirements I came up with:
- Strong enough to take a beating without the sights or rail being damaged
- 16" barrel chambered in 6.8mm w/ midlength or intermediate DI gas system
- A good bolt carrier group
- Lightweight, free float rail system w/ continuous upper rail
- Ambidextrous lower receiver
- Grenade launcher compatibility
- Flash minimizing muzzle device
- Good charging handle
- Comfortable grip and stock
- Multiple sling attach points
So, I think one day, when I get the money, I'm going to go ahead and build this rifle or have someone build it for me. Here's what I have so far:
Rainier Arms Ultramatch billet upper
***16" 6.8mm midlength barrel***
POF-USA P-415 ambidextrous lower receiver
Daniel Defense 12" RIS II rail system
LMT 6.8mm BCG w/ enhanced bolt assembly
Magpul CTR or LMT SOPMOD stock kit
BCM midlength gas tube
Vortex flash eliminator muzzle device
BCM Gunfighter Mod 3 charging handle
Troy rear folding BUIS
Daniel Defense or LMT rail mounted front fixed sight
Daniel Defense rail swivel attach point
Daniel Defense lower parts kit
BCM extractor spring upgrade kit
Daniel Defense or Noveske rear swivel attach point
Magpul MOE grip
The only thing I don't have nailed down is the brand of barrel I'd like to use. Any recommendations? I saw a bunch of custom builders elsewhere in this thread, but from their websites it it looks as if they'd be unlikely to use my choice of parts.
BLACK LION
10-06-09, 11:38
Mark,
While I cannot speak for ARP, I have communicated with him on several occasions, I know he is very busy, but he will get back to you. He might have simply overlooked it, intending to get back to you.
It has happened to us all at some point. I suggest you try contacting him again and see if you get a reply.
Took the words right outta my mouth.
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