The 6.8SPC Experience

A reader asked me to relay my experience with the 6.8 Special Purpose Cartridge, since I shot the high-power match at my club with the 6.8 upper.  I bought the upper a few years ago at the Gun Blogger Rendezvous, because Uncle had brought it out on behalf of Ko-Tonics (who are no longer in business).

I shot a high-power match this weekend with it, since I had plenty of 6.8x43mm loaded up, and didn’t feel like loading up any 5.56.  We had a Garand match first.  Shot decently with that, with a 250 out of 300.  Shot awful with the 6.8 AR, but that was my fault, not the gun or the cartridge.  My impressions of 6.8:

  • The recoil is heavier than 5.56x45mm, but it’s not nearly as much as a 7.62x51mm.  On the loads I use, it only has about two more grains of powder than the 5.56 loads I make with the same powder.
  • Shooting a match out to 200 yards, like we do at my club, there’s no perceptible difference between 5.56x45mm and 6.8x43mm.  I think you’re probably at a disadvantage because of the heavier recoil of the 6.8x43mm.
  • Shooting out to 400 yards, I can’t say I have much experience with the 6.8, but when I’ve had the opportunity to do it, the 6.8 seems to hit more reliably at that distance than 5.56x45mm.
  • Past that distance, you’re really beyond what an intermediate cartridge is meant for without using specialized bullets and loads.  High-power shooters that shoot a full 600 yard match use special loads and bullets that are too long to even be loaded into a magazine properly, which is fine for slow-fire stages.
  • The 6.8 SPC round would be effective at hunting medium sized game, if that’s what you’re interested in.  The bullet you use is identical to the .270 Winchester, although it’s not as powerful a round as would be used in deer hunting, but at distances you’d typically take a deer from, it would be effective.

I think 6.8SPC would make a good round for replacement of the 5.56×45, if the military ever decides to go the route of a larger caliber intermediate cartridge.  I’m more skeptical of its utility in high-power competition, because I’m not sure what advantage it offers over 5.56.  Keep in mind that my club only goes out to 200 yards, so others who might have more experience with longer range shooting might have a different impression.  I can’t speak to it’s performance vs. 5.56x45mm out past that distance, because I just don’t have much experience with it.

If you’re interesting in getting yourself a 6.8 SPC upper, or making yourself a complete 6.8 AR, Bison armory is a good supplier.

14 thoughts on “The 6.8SPC Experience”

  1. I built a 20″ 6.8 upper with a Bison Armory barrel, along with a 16″ 6.8 upper from AR Performance… can’t wait to try them out, I still need optics, bullets, and powder, and they’re competing with all my other gun related projects :-D

  2. I’ve got a 6.8 upper, and for the life of me I can’t figure out anything it’s especially good at.

    At longer ranges, it’s only slightly superior to the 5.56, and inferior to the 7.62. At very long range, it’s REALLY inferior.

    OTOH, the 6.5 Grendel seems to be the best of both worlds: very accurate at all ranges including out past a kilometer, good enough energy to stop most N. American mid-sized game animals out to 500 meters or so.

    It’s a shame the Army Ordnance Corps still suffers from NIH. I think the 6.5 is far better, and with a bit of tweaking the Army could do quite well with it.

  3. Based on ballistics and ammunition availability, I can’t imagine choosing a 6.8SPC over 7.62×39 in an AR. The 6.5 Grendel, like Flighterdoc said above, has real potential, and I’d hop on that in a heartbeat if ammunition became more widely available.

  4. My understanding is the 7.62×39 head size is too big for it to be used with standard AR components. All you need with 6.8 is a bolt change and a barrel change. The other parts are the same.

  5. I’m biased but the issue with 7.62 is also magazines. None feed well, except the frankenmags and good luck finding them. I had one and liked it but ultimately it was just too unreliable.

    The grendel does have potential but the cost since the maker licenses the caliber are high for both guns and ammo.

  6. The Grendel attitude reminds me of Sony Beta and MAC OS. Both were better then their compeditors, but both lost the war because of stupidity on the part of the developers.

    Everything I have read regarding the Gredel says that it is a better cartridge then either the 5.56 or the 6.8. ANd for some purposes better then the 7.62X51.
    I have friends who shoot precision matches and the rounds they use are very similar to the Grendel.

  7. The 7.62×39 based cartridges require a bolt thats been opened up too much, and wouldnt pass reliability requirements. Also, they won’t feed properly on full auto due to the straight section of mag required of the AR’s lower.

    Sebastian: have you tried loading up speer’s 90gr TNT? They give good results, and really scream when used with the right loads. Looking it up, you should be able to get around 2900fps with a Ko-Tonics barrel. That load should give a flatter trajectory than even a .308, which makes it fine for use to about 600 yards. Those loads will keep pressure levels under 55kpsi (the spec). If you want to push it, you might be able to depending on powder. With H322 I could not, even in 100+ deg Phoenix heat due to a lack of case capacity. But other powders might work ok.

    Also, don’t expect stellar accuracy from some powders. H322 was great for accuracy, but H335 sucked, same rifle, same case prep/cases, same shooter, same bullet, but the group sizes would open up at least 1/2 moa.

    The beauty of the 6.8 is that it uses much faster powders than the 5.56, which means its not handicapped as badly by a shorter barrel.

  8. Mike, I didn’t know about the reliability requirements, and that’s a real problem. Thanks for letting me know!

  9. I thought the problem with the Grendel is it doesn’t do well in short barrels.

  10. I’m an Illinois Highpower shooter, and I remember John Holliger messing around with a 6.8 SPC based wildcat (6.5 Holliger, 6.8 Holliger?) in a spacegun format. I only remember seeing it out one season, I believe it was deemed a failure. Shot very well, but I don’t think it achieved the long range results he wanted.

  11. I’d read an early report on the 6.8SPC vs the 6.5 Grendel, which seemed to give the definate edge to the Grendal. I was wondering why I hadn’t seen it more, I guess (if SayUncle is true) they’re shooting themselves in the foot. Too bad. I could see the Grendel totally sweeping away both the 6.8SPC & the 5.56.

    Anyone else have any more reports, personal or otherwise, on the 6.5, especially vs the 6.8?

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