6.8 SPC AR owners please

Discussion in 'Rifle Country' started by Rokman, Sep 12, 2008.

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  1. Rokman

    Rokman Member

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    My question is, are you happy with this caliber, or do you wish that you chose something else? Are you satisfied with this combination or do you wish that you would have moved up to an AR10 class caliber, or just stayed with the 5.56? I have two ar15 's (rifle and carbine) in 5.56 and would like something else with a little more oomph in the ar platform. I handload most of my ammo, so some of the less common calibers woud be okay if I could get all of the necessities.
     
  2. kentucky_smith

    kentucky_smith Member

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    I've had both uppers in 6.8 and 6.5 Grendel. I liked both, but liked the Grendel better.
     
  3. Sam Adams

    Sam Adams Member

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    What did you pay for the Grendel & where?

    What did you like about it better?
     
  4. Rokman

    Rokman Member

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    I have considered the 6.5 Grendel, but I want to easily be able to get brass. I have been researching the various calibers such as 450 Bushmaster, 458 Socom and the AR10 calibers such as 6.5 Creedmoore and .260 Remington. I have concluded that my best bet would be the 6.8, or step up to 7.62 with a much heavier rifle.
     
  5. rbernie
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    rbernie Contributing Member

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    I have several ARs in 6.8SPC, and I prefer them over my 223 and 7.62x39 ARs for any use where terminal ballistics count.

    I chose 6.8SPC over the 6.5 Grendel for several reasons, not the least of which was due to component/rifle availability. It also helps greatly that I shoot a lot of 270; I interchange lightweight bullets between the two chamberings in my handloads. I do not shoot over 300 yards, and the ballistic advantages of chamberings like the 6.5 Grendel hold little profit for me relative to the extra cost and reduction in component suppliers that they imply.
     
  6. kentucky_smith

    kentucky_smith Member

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    My current Grendel setup was a stainless barrel and bolt combo from Alexander Arms, put it together myself with the rest JT Dist. parts for <$500 for a complete upper.

    The big turnoff for me about the Grendel was availability, but seems Bill has lightened up a bit. JT Distributing is building uppers, as is Charles Daly. Centerfire had some complete 16 and 20" uppers for $529 (with bcg).

    http://www.centerfiresystems.com/ARUP-65-16A3.aspx
    Another factor is I mostly deer hunt with a sporter swede, so I can handload my 120 gr Core-Lokt bullets in either cartridge.

    The whole SPC I, II, DMR, which twist, how many rifling, turned me off the 6.8. Probably should have quit reading the AR variant forum on Arfcom and kept what I had.

    Regardless, either will do a good job.
     
  7. Rokman

    Rokman Member

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    After researching brass for the 6.5 Grendel, it appears that it is about a dollar a round. Does that sound correct? If so, that will push me away from it.
     
  8. iamkris

    iamkris Member

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    I researched both calibers heavily and initially decided on the Grendel. Seemed to have all the terminal ballistic advantages of the 6.8 but with better exterior ballistics. I bought an AA Overwatch upper and built an 18" SPR.

    Building the upper was a nightmare...what with many delays and difficulties in getting parts (I only bought top-end parts for it). Brass was expensive, reloading info was scarce. In the end, accuracy was good but not mythical like the caliber has been built up to be. That is with factory and many variations of reloads.

    I realized I was trying to get a lightweight, handy CQB caliber with better performance than the 5.56 as well as a great long range caliber. While not completely mutually exclusive, it is difficult to do both. I still think the Grendel is an interesting caliber for what I REALLY WANTED TO DO (better ballistics, terminal out to 500 yards) the Grendel wasn't it. I sold the uppers and built a 6.8 upper.

    It is showing very good accuracy (hovering right around MOA), has better terminal effect than 5.56, can hang with a 308 for the distances that I'm interested in and has the advantage of much wider distribution. Grendel needs to be less "exclusive" if it wants to make up the gap.

    I've also decided that if I want a long range rifle semi-auto rifle, I should build a long range semi auto rifle...probably a AR10 in .260 Rem or 6.5 Creedmore.

    I had a very long phone conversation with John Holliger of White Oak Armament. There's a lot of talk about the SAAMI vs. SPC-II chamber and the pressures created in each...his view is that it is a lot of hoo-haw about nothing unless you are trying to hot rod the cartridge and make it into a .270 Win.

    Here's my 6.8 SPC AR

    • DPMS 5.56 lower
    • Stag/CMT M4 upper
    • Badger Gen II TacLatch
    • RRA 2-stage NM trigger
    • VLTOR stock
    • WOA 18" SS SPR profile barrel and bolt
    • PWS FSC30 flash hider / comp
    • YHM front sight
    • Brownells HK-type rear sight
    • ERGO grip
    • Magpul triggerguard
    • MI low profile gas block
    • YHM FF rifle-length quad rail handguard
    • MI sling mounts
    • EoTech 511 (now with a 4x magnifier)
    • PRI mags


    2w6ap8w.jpg
     
  9. HorseSoldier

    HorseSoldier Member

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    Kind of depends on what you're wanting to do with that extra thump from an AR style rifle. 7.62, or 6.8 Rem SPC, or 6.5 Grendel will all do pretty good service on deer or hogs, judging from what various posters on here have said (and provided photographic evidence of . . .).

    All three of them will work well at real combat kind of distances. If you're looking for a long range shooter, 6.5 Grendel is better than 6.8 Rem SPC, and 7.62 is better than either of them (no matter what the Grendel fanboys say).

    For a fighting/tactical carbine, the relationship is reversed -- 7.62 is poor, 6.5 Grendel is better, 6.8 Rem SPC is the best of the bunch.

    Now, 6.8 or 6.5 allow the same use of your existing lowers, while the AR-10 requires a whole new gun. Higher set up cost, but cheaper ammo or ammo making supplies once you're up and running, I'd think.

    So, like I say, depends a whole lot on what you're wanting the gun to do.
     
  10. Rokman

    Rokman Member

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    Now that's the kind of info that I am looking for. I am thinking that I may hunt with this firearm, so I am looking for something larger than 5.56, but probably not up to AR10 level. I am not a soldier, so combat is out of the question. Though I would shoot a bad guy if the need be. Can someone tell me what an SPC-II chamber is?

    Iamkris- that is an excellent looking 6.8 SPC. Thanks for the pic.
     
  11. mtruette

    mtruette Member

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    I like It

    I have just purchased a 6.8 AR and had it set up like I wanted. I have the Douglas barrell with a 1:11 twist and just shot enough to break the barrell in. It is good for 1" group at 100yds. I got some extras on the rifle and enjoy shooting it. The first reason I bought the rifle is I just wanted one. The second reason is that I work as a Deputy Sheriff and I am impressed with the weapon over the 5.56. With the right ammo it will do most anything I want it to from penetration to knock down. Even hunting certain game. I do plan to try it out on hogs and possibly a deer this season. I am very pleased with the rifle and plan to experiment with different ammo.

    You will find AR15, AR10, 6.5 and 6.8 fans out here. It is a matter of choice and the choice is yours. Good hunting! :)
     
  12. iamkris

    iamkris Member

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    It is a long and convoluted story...the short answer is:

    * In the "early days" most 6.8 SPC barrels had 1:10 rifling. There were accuracy issues (over stablizing they lighter bullets) and some pressure issues due to "confusing" SAAMI chamber spec.
    * Enter the trend for most good manufacturers moving to a 1:11 barrel. Accuracy issues seems to resolve themselves but there were still some overpressure reports. Most seemed to be related to 1) heavier bullets, 2) thicker brass 3) hot-rodded loads
    * The SPC-II chamber is a "solution"...it has a more generous neck diameter and a longer throat/leade.

    As I understand it, if you have a SAAMI chamber and 1:11 barrel, you are good to go for 99% of loads. SPC-II seems to clean up most of the rest of the issues.

    Here's a short history from 68forums.com

    What hasn't helped recently is an issue that KoTonics/Cardinal Armory has had...they are a major manf of barrels/uppers. They've recently discovered that their subcontractor that has been plating their barrels has not been doing it to spec. That has caused some potential issues with dangerous pressures being created. That's too bad...Cardinal is a stand up company and has been very forthright about what is happening. They're really taking it on the chin.

    http://www.68forums.com/viewforum.php?f=1&sid=2aea2da3623193658110da070770bae6
     
  13. Rokman

    Rokman Member

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    Hopefully, this will be my last question. I am thinking about purchasing a RRA midlength in 6.8. It appears that the barrel is a 1:10 twist. Will this twist rate be okay?
     
  14. Tarvis

    Tarvis Member

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    I have been considering getting a 6.5 or a 6.8 but it seems like it's too difficult with all the options. It is a great idea but seems like there needs to be a consensus on what the twist and chamber should be.
     
  15. Bigfoot

    Bigfoot Member

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    If someone already owns a 1:10 twist barrel go ahead and keep it. I'd have the leade lengthend out to SPC ll specs though, it's a cheap fix.

    No way I'd buy a 1:9.5 or 1:10 barrel new. You wouldn't believe the velocities guys are getting with SPC ll and DMR chambered 1:11, 1:12 and 1:13 twist barrels. Yeah, 270 lite works for me. I'll be building one very soon.
     
  16. SC_1911Shooter

    SC_1911Shooter Member

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  17. Rokman

    Rokman Member

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    That is some really good info guys. I think that I will steer clear of the 1:10 twist barrels. I am still really interested in this caliber, but will do something in a different barrel.

    Thanks:cool:
     
  18. jerkface11

    jerkface11 Member

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    Olympic makes AR15 uppers chambered in the WSSM calibers. The only downside is the 7 round mags.
     
  19. jordan1948

    jordan1948 Member

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    I'd go with the 6.8, reason being I've seen how they perform, I haven't seen the 6.5, also there's a SLIGHT chance the military will start using them more, if that be the case ammo with be plentifull(though surplus but it's good for just havin' fun with).
     
  20. rbernie
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    rbernie Contributing Member

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    Cardinal Armory is the place to start and end your shopping for hard parts. Enjoy! :D
     
  21. amprecon

    amprecon Member

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    I'm gonna wait until the 6.8spc ammo prices drop and it becomes more widespread before I take the plunge. I'm looking hard at the Robinson Arms XCR with an Acog TA11E or TA11F in 6.8SPC to be my be-all-end-all-do-it-all rifle.
     
  22. UnTainted

    UnTainted Member

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    6.8spc barrel legnth ballistics:

    115 grain

    20” barrel: ave vel = 2561 fps; 10 fps extreme spread

    16” barrel: ave vel = 2525 fps; 18 fps extreme spread -- lost 36 fps from 20"

    12.5” barrel: ave vel = 2384 fps; 12 fps extreme spread -- lost 141 fps from 16"

    10” barrel: ave vel = 2265 fps; 27 fps extreme spread -- lost 119 fps from 12.5"

    7.5” barrel: ave vel = 2035 fps; 27 fps extreme spread -- lost 230 fps from 10"

    FRAGMENTATION TRESHOLD - 1530-something fps

    found these stats on another board some time ago, and copied the chrono data the reloader had done with different uppers (noveske, if I remember correctly).
     
  23. Bigfoot

    Bigfoot Member

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    Noveske is a very good smith but he's still using the old spec barrels.

    Compare that to this data, everything here was tested using pressure trace equipment. The first page is with SSA commercial loads that everyone can buy. They will only sell thier combat loads after SSA makes sure that they are not used in Remingtons fouled-up :cuss: SAMMI spec barrels.

    Check out the velocities with handloads on the second page. These guys are pushing the 110s to over to 2900 fps. All with one eye on the strain gauge data to keep it safe.

    See that 80 gr bullet at the bottom on the second page doing 3400 fps? That's a TSX type bullet from So Africa, very expensive. Why mention it? Because Barnes is soon going to restart production of thier old 85 TSX FB that they made for a short while. It will be much cheaper and should do 3200 easily. That's one flat shootin SOB. Blacktail deer beware. :D

    You don't trust the penetration of an 85 gr TSX? Then shoot the 110 TSX at over 2800, some are getting over 2900. Mule deer and hogs beware. :D

    Noslers 110 Accubond is out now. A 110 bonded hunting bullet with a decent BC at 2800-2900. Plus the 6.8 can shoot the shorter 130s at 2500-2600. Assuming the proper spec barrel is used.

    Do you think these bullet manufacturers (who know thier markets very well) are bringing out these light for caliber .277 bullets for the 270 Win or 270 WSM? No, the market spoke and the 6.8 is a winner.
     

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    Last edited: Sep 17, 2008
  24. ForneyRider

    ForneyRider Member

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    How about 7mm TCU?

    .223 brass with 7mm bullet.

    7mm bullet goes from 100gr(TNT) to 170gr(Norma), and maybe 175 as a round nose.

    OAL is 2.5 just like .223

    Oops, I guess TCU is a blown out cartridge.
     
    Last edited: Sep 17, 2008
  25. bedlamite

    bedlamite Member

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    http://68forums.com/

    I just recently finished a 6.8 SPC with a Cardinal lightweight barrel, YHM low profile gas block, Clark carbon fiber handguard, CMT upper & BCG, RRA trigger, and an ACE stock. It's 6 lbs with the scope. I have yet to take it to the range, that will probably be this weekend.

    AR-68-1.gif
     
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