View Full Version : 6.8 SPC Build
So I have decided it is time to buid another AR and I figure since I am doing it why not in 6.8 SPC. So here comes the choice.
Barrel - I want something in 16" and probably 1x7.
Being I have never worked with this round before I don't have a clue what would be a good barrel for the rifle.
Any suggestions would be great. Thanks
They were advertising that they were making a 6.8 and their 5.56 fit the discription you listed. Perhaps they sell the barrel by itself.
Semper Fi!
watersniper
06-25-06, 10:32
1-7 twist is too fast for 6.8SPC unless you are going to try and shoot the heaviest of heavy .270 bullets... But then your velocity will be in the 1500-2000fps range... 1-10 twist is fast enough... I'm not even sure they offer 1-7 for .270 caliber??? Most are using bullets in the 90-115gr. range with a few tinkering with 130gr. .270 bullets. Hornady was supposed to come out with a 120gr. bullet.
CapnCrunch
06-25-06, 11:25
Twist rate for the 6.8 should be somewhere between 1/10 and 1/11. ABS, Douglas, and Noveske all make fine 6.8 barrels. Midlength gasport position works best for the 16".
What muzzle device you plan on using will determine what thread you'll want to go with.
I have not determined what muzzle device I am going to use yet because I haven't finalized the budget on this one yet. Anything you want to add to help me decide is great. Thanks
CapnCrunch
06-26-06, 09:34
Honestly, there are a lot of choices.
In 1/2x28 you have the Troy Medieval, the Surefire FA68A Suppressor Adaptor, and you can have pretty much any other FH reamed out to work.
In the mil thread you've got the .308 Phantom and Vortex, the Surefire FH762S Suppressor Adapter, and scores of others.
I think I am going to go with the 1/2x28. I was pretty sure I was going with the FA68A so that will work. Thanks for your help Captain.
In addition to the mid-length gas system (except for shorties), make sure you get a barrel with the M4 feed ramp extensions. This will ensure 100% reliability across all ammo types. Also, I have shot form 110gr to 150gr through my 1X9.5 with excellent accuracy.
Good luck! The 6.8mm is a hell of a lot of fun.
Stephen
If your looking for ammo with your new build you may want to check out www.midwayusa.com they have 6.8 spc. silver state armory ammo for about $150.00 for 200 rounds. If you have the chance to reload I would do that.
Dennyguns and recon barrels in stock for $355.00. I'm thinking about purchasing a 16 inche ss barrel from jtac for about $355.00 and that includes the bolt. Just some information for you.
From,
Joe....
I'm going to check out that ammo for sure. Thanks for the heads up.
Really do not think threading a 6.8 barrel 1/2-28 is a wise idea as your barrel thickness at the threads will only be .1115". But that is just me.
.500"-.277"=.223/2=.1115"
Thanks for the heads up, what would you suggest instead?
Thanks for the heads up, what would you suggest instead?
The .mil specified 5/8-24 for the 6.8 SPC project. This info is taken from Zak Smith's 6.8 info website.
What muzzle brakes / flash-hiders are available for 6.8SPC (5/8-24)
The MSTN/PRI Quiet Control ("QC") Comp. This is a modern comp and should be as effective as the JP BC Comp, the Miculek comp, or the Benny Hill comp (which are only available in 5.56).
The Vortex flash-hider. Smith Enterprises' Vortex for the Remington 700 PSS (.308) will work with 6.8SPC. You must request some custom machine work to match the shoulder-muzzle dimensions. It is threaded for 5/8"-24tpi.
Phantom 308 flash hider.
OPSINC 4-port brake. Pictured above, this is an older-technology brake.
OPSINC 2-port brake. This brake has only one chamber and is primarily designed as an attachment point for an OPSINC suppressor. OPSINC suppressors are only available to LEO & Military in the US because OPS is located in California.
http://www.hunt101.com/img/421978-big.JPG
Armalite AR-10 muzzle brake
This should be a good start as most 6.8 SPC barrel being sold as of late are 5/8-24. .625"-.277"=.348"/2=.174" as a wall thickness.
You will really like a 6.8 SPC. Everyone I have let this thing loose with is building one. I will very soon use it exclusively as my primary carbine. It's easier to outfit one guy than the whole Army I suppose.:)
I managed to squirrel away 1500 rds and 1000 rds of brass to reload. It is exceptionally accurate IMO. I have to get the chrony out but it seems to have a good bit of steam.
http://i20.photobucket.com/albums/b243/conndcj/stag686.jpg
http://i20.photobucket.com/albums/b243/conndcj/stag685.jpg
http://i20.photobucket.com/albums/b243/conndcj/stag684.jpg
http://i20.photobucket.com/albums/b243/conndcj/stag681.jpg
BTW, IIRC Ops Inc cans are GTG everywhere now as are Surefire. The CA restriction is over.
Stag lower and LPK
Colt M4 upper
CMT bolt carrier and MP bolt
LT 13.2
Noveske 16.1 Recon barrel cut back to 15 with Ops 4 port brake
Matech rear and troy front sights
Magpul PRS stock
TD bipod
PRI 25rd mag
NF 2.5-10 NXS w/NP-R2 reticle in LT SPR mount
My 6.8 build:
-PRI/Douglas SS 18" SPR barrel/CMT M4 upper
-Lauer lower
-Leupold Mk4 4.5-14x50 LR/T with ill. TMR ret.
Plus a whole lot of LaRue stuff!
http://i1.tinypic.com/205vd6u.jpg
http://i1.tinypic.com/205vy85.jpg\
CapnCrunch
07-22-06, 11:20
Really do not think threading a 6.8 barrel 1/2-28 is a wise idea as your barrel thickness at the threads will only be .1115". But that is just me.
.500"-.277"=.223/2=.1115"
Using 1/2x28 is a non-issue. I've been using 1/2x28 threaded 6.8 barrels for very abusive testing, and if it was a problem it would have shown itself by now. I've ran them suppressed, sustained fire, etc.
I mean, if it was a problem do you think Surefire would be using that thread for the FA68A cans?
Using 1/2x28 is a non-issue. I've been using 1/2x28 threaded 6.8 barrels for very abusive testing, and if it was a problem it would have shown itself by now. I've ran them suppressed, sustained fire, etc.
I mean, if it was a problem do you think Surefire would be using that thread for the FA68A cans?
Considering Surefire is relatively new to the suppressor game, there are bound to be some growing pains. Couldn't it also be possible Surefire went with the 1/2-28 threads as a marketing plan, as to offer so-called cross compatibility with the 5.56? Do any other companies offer suppressors for the 6.8 with the 1/2-28 thread as a standard?
Really not sure, but if the .mil spec'ed a different thread pitch maybe they know something that Surefire doesn't or vise versa. My first 6.8 barrel from WOA is threaded 1/2-32 and there seems to be no issues, so you are probably right. Hmmmmm........ makes me think that I should have my other 6.8 barrel threaded to 1/2-28 (currently a 5/8-24). It would definitely open up the options for muzzlebrakes.
CapnCrunch
07-23-06, 12:22
I've heard that the mil 5/8x24 thread was to keep folks from trying to put 5.56 flash suppressors on the 6.8 barrels. Funny thing though, all of the A2 FS that I have are more than generous enough to allow the 6.8 to work fine.
BTW, just compared a FA556A suppressor adapter to a FA68A one... Perfect match. Exact same flash suppressor.
Cohiba,
That is one beautiful 6.8 carbine! I'm trying really hard to not like the 6.8SPC and you're not helping...:D
In addition to the mid-length gas system (except for shorties), make sure you get a barrel with the M4 feed ramp extensions. This will ensure 100% reliability across all ammo types. Also, I have shot form 110gr to 150gr through my 1X9.5 with excellent accuracy.
Good luck! The 6.8mm is a hell of a lot of fun.
Stephen
Would you mind posting the laod data you use for the heavier bullets?
PM inbound
Thanks
Tim
TimP, your Noveske 6.8 is almost done!
For anyone interested, I have one Noveske 16" 6.8 barrel, 6.8 BCG and special order 6.8 Vortex in stock.
C4
I had my WOA 12.5" SS barrel re-threaded for 1/2x28 with no adversed affects.
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