6.8 SPC II Custom Build Rifle

There have been countless wildcat cartridges over the years.  One recent trend has been the various efforts to modify the standard AR15 to shoot a heavier, more lethal bullet.  The crazy hype surrounding the 300 Blackout is but one example.  For my money, the 6.8 SPC is the best of the lot for general all-around use.

The 6.8 SPC was developed by Remington and the US Military to enhance M16 5.56 terminal performance.  Essentially, it is a .30 Remington cartridge case (shortened) with a .277″ bullet with the same overall length as the 5.56.  To modify an AR style weapon to shoot the 6.8 cartridge you replace the barrel, bolt, and magazine.  Of course, many manufacturers now sell complete 6.8 SPC uppers.

The platform has quickly gained acceptance among hunters.  Performance is good out to about 300 yards and the AR style rifle works especially well for hunting hogs and varmints where the modular design allows the mounting of lights and other accessories.  Terminal performance is far superior to that of a standard .223 / 5.56.

My favorite hunting round?  Silver State Armory 110gr Barnes TSX Tactical Load:

Ballistic Coefficient: 0.323
Muzzle Velocity (fps): 2650
Muzzle Energy (ft-lb): 1717
100 Yards (inches): 2.9
200 Yards (inches): 0.0
300 Yards (inches): -9.6

Custom Build.

Gun nuts love the AR15 because of how easy it is to customize.  Mine started off as a Rock River Arms A4 Varmint chambered in .223 / 5.56.  I quickly went to work modifying it into a custom hog-hunting weapon:

  • E.R. Shaw 16″ stainless steel recon barrel with black Gun-Kote.
  • 4-groove, 1:11″ twist.
  •  Yankee Hill A3 upper receiver with extended M4 feed ramp.
  • LMT bolt.
  • Magpul MOE furniture.
  • Troy Alpha Rail 11″ forend.
  • Magpul ASAP Sling Mount with Blackhawk sling.
  • Geissele Super Semi-Automatic Enhanced trigger.
  • Aimpoint CompM4.

Stay tuned for upcoming reviews on the Geissele trigger and Aimpoint CompM4.  Suffice it to say they are superior!

What do you think of the 6.8 SPC?  How does it compare to the 6.5 Grendel and 300 Blackout?

6.8 SPC
6.8 SPC
Aimpoint CompM4
Aimpoint CompM4
6.8 SPC
6.8 SPC

Geissele SSA-E Trigger

Geissele SSA-E Trigger
The following two tabs change content below.
Publisher of Tactical Gun Review and Texas Outdoors Network. Mike wisely spent his youth hunting and fishing in South Texas.

Latest posts by Mike Coker (see all)


8 responses to “6.8 SPC II Custom Build Rifle”

  1. Mike Coker Avatar

    Ammo availability is certainly an issue. 6.8 is becoming more mainstream and easier to get. That is why some guys won’t shoot anything other than military rounds.

  2. Cal Greco Avatar
    Cal Greco

    It’s funny but 6.5, 6.8, .300 black out or whisper where are they and how much! I go to Walmart and no where to be found. But if I can get my 7.62 by 39mm every time and cheaper. This is not an AR to AK comparison either just a fact that if we could make a better AK then we would always have ammo around the world. Were not our own troops using the enemies AK’s!

    1. Charles Coker Avatar
      Charles Coker

      Well, true.. I still personally like the 6.8 for hunting out of an AR platform.
      It is probably a good idea for every able bodied American male to have an AK and know how to run it.

  3. Mike Coker Avatar

    Priceless > AF female who was walking around with her magazine sticking out her M9 well because she jammed it in there backwards…she was “security forces”

  4. Cary Kieffer Avatar
    Cary Kieffer

    From a military point of view the 6.8 (and all the rest of them) is a waste of money and time. Probably the brainstorm of a few spoiled boys who had a budget surplus and wanted a new toy to play with. I will explain.
    Colonel Jeff Cooper coined it best when he said something to the effect of “you don’t need a better gun, you need to use the one you have”. Perfect!! Marksmanship is dead in 3 of the 4 branches. The Corps is the only one that still has a real program intact and it in my opinion is watered down. Troops don’t need a more lethal round, they need the training to properly employ the 5.56mm rifles they have now. I was always appalled watching the total lack of know how by US personnel in my travels. There are way too many untrained people issued m4’s. From Army privates that fresh out of “training” couldn’t field strip their rifle to their staff NCO’s who couldn’t clear a chamber right and fired rounds regularly into the clearing barrels. I’ll never forget an AF female who was walking around with her magazine sticking out her M9 well because she jammed it in there backwards…she was “security forces” she said…..That leaves a good feeling in your stomach…
    Another point would be logistics….we already had the 7.62×51 for decades…You want more power? There it is and it’s already in the system. Go back to that and stop trying to invent the gadget that will make up for human shortcomings. The Gov’t is famous for that practice, trying to invent something to make up for our lack of knowing what the hell you are supposed to be doing. Instead of spending another dime on this stuff and all the bullshit creature comforts they think we need it’s time to spend that money on actually teaching people to fight.
    My Solution: I have said this for years…Ranges should be open on all bases mon-friday and half day on Saturday. They should be stocked with the usual TO&E weapons. Anytime you want, any time you have an hour of “ass burnin’” time combat troops should be heading to the range for some practice on KD courses and combat courses. Not recleaning a clean barracks because there was nothing else to do. You should be able to check in, get a score sheet and be tracked of your progress…it’s a simple as keeping a couple good PMI’s around the place running it and teaching real skills that will improve our on the ground capability without dickin’ around trying to find the 6.8 magic trick that won’t work anyway when in the hands of the same untrained troop. In short, TRAINING with a 5.56, NOT a new fandangled cartridge.
    I don’t know anything about hunting so I cannot comment on that but from a military standpoint it’s time to get back to the basics of making everyone a rifleman.

    1. Charles Coker Avatar
      Charles Coker

      Nicely put sir.

    2. 53GR Avatar

      I agree except for one modification:
      The M855 5.56x45mm cartridge is not good for longer range firefights in places like Afghanistan. Out of a M4 barre, the M855’s velocity will fall below fragmentation threshold after about 100 meters. So if you’r engaging targets out at 300 yards, it’s great that you can hit them, but you may simply be poking small holes in them.
      An obvious choice to remedy this is a switch to the 7.62x51mm round, which will retain energy at distance. However, the logistical implications of such a switch are massive. Another option would be to widely distribute the Mk 262 round (77-grain 5.56x45mm) that has better terminal ballistics at range.
      Of course, there’s a third option. Since we’re not actually fighting soldiers in Afghanistan, we could use hollow-tip bullets. The insurgents we face don’t wear uniforms, don’t openly display arms, and aren’t covered by the Geneva Conventions. We only need to use FMJs when we’re fighting actual soldiers covered by the GC.
      Just sayin’….

Leave a Reply

Your email address will not be published. Required fields are marked *