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Thread: Anybody still shoot 6.8?

  1. #101
    Join Date
    Apr 2012
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    NC
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    I have followed both cartridges since they were introduced. To be honest, both the 6.8 SPC and 6.5 Grendel are excellent hunting cartridges for any distance at most of the deer or hog hunters I know would ever feel confident to shoot. People who are just learning about them missed the most entertaining era of these two cartridges, though. For their first five or ten years, there was a massive rivalry between their users that went so far that each side started changing the others Wikipedia entries! Wiki eventually figured out what was going on and froze the entries for a while. It was like watching a soap opera.

    The 6.8 SPC has a longer, smaller diameter case that has slightly thicker walls near the base. These were deliberate choices from its developers. This makes it feed slightly more reliably through the AR15 magazine well since that part of the weapon was optimized for the smaller-diameter 5.56x45 case. It makes the bolt and the case a little stronger to handle the abuse of overpressure rounds. The 6.5 Grendel has a shorter, larger diameter case, but this is what allows it to use longer, more streamlined bullets for long distance target shooting. These were also deliberate choices from its developers. These days, Grendel bolts last just fine if they are not abused. It is useful to keep a spare extractor. More care must be taken to keep the magazines feeding well, but some users have never had a problem.

  2. #102
    Join Date
    Jul 2014
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    Quote Originally Posted by Disciple View Post
    If expansion range is your measure why not shoot 77 grain 5.56?
    I was thinking more about the max effective range for hunting, which is the reason I built a 6.8. I wouldn't hunt with a 5.56 and it would be illegal in my state anyway. If I'm grabbing an AR for defense it will be 5.56, but I doubt I'll be making 400+yd shots.

  3. #103
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    Feb 2015
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    6.8 SPC is a great wild hog cartridge out to 200 yards.

  4. #104
    Join Date
    Sep 2015
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    Some of the premium 6.8 projectiles will expand out to about 400 yards. Beyond that no dice on expansion for either 6.5 G or 6.8 SPC, that's about the limit due to velocity unless someone comes up with a heavy high BC projectile with a very soft jacket designed to expand at very low velocities. Most common 6.8 projectiles will expand or fragment reliably to around 300 yards. The same cannot be said for 5.56 loads until you get into the premium stuff. But even then, the diameter of expansion and damage done to the target is simply NOT as ideal as 6.5 G or 6.8 SPC.

    There's plenty of people on the 68forums and 65grendel that have taken hogs out at 300 yards or more with premium loads and deer out to 400. Suggesting it's only good to 200 is not accurate, there's a lot of good hunters that say otherwise. Against human targets? 500 to 600 yards (basically any range you can practically hit the target in a vital area). Non-expanding ammunition (in this case, because velocity drops too low to fragment / expand, not because it's a FMJ) to a vital organ on a human (heart, liver, CNS) is absolutely lethal and will still rapidly incapacitate them. Expansion / fragmentation is more important however at closer ranges because you ideally want instant incapacitation as their threat level to you is higher than at longer ranges. I think it's unlikely an enemy combatant will take a hit at 500 yards and accurately return fire until they expire. But at 10 yards...if they are still fighting they can still send rounds your way with a reasonable probability of hitting you.

    Most properly built 6.8 / 6.5 uppers are sub MOA capable, so they are plenty accurate to take those longer shots pending you know your holds and drift. I think it has a lot more to do with shooter competency than the cartridge or rifles capabilities. Most tactical guys will shoot 5.56 out to 300 or more yards and that's not exactly an ideal medium range cartridge, I'd say it's more of a close to close-mid range cartridge due to its lackluster terminal performance at those intermediate ranges. The available KE and in particular momentum are quite low at true intermediate distances. Can it still be lethal? Sure, but it's far from IDEAL at those ranges, wounding and penetration is vastly reduced.

    6.5 Grendel has similar ranges to 6.8 SPC where projectiles will expand (for all intents and purposes there is no difference practically between the max distance either can still achieve expansion), however 6.5mm's wounding is NOT quite as good overall, especially through barriers. Military testing on a variety of 6mm and 6.5mm projectiles showed that terminal performance was not as consistent or desirable as 6.8mm, 7mm and 7.62mm, but that 6mm and 6.5mm were the most accurate (due to their optimal exterior ballistic properties).

    What works FOR a projectile while flying through the air works AGAINST it when impacting the target. Longer and smaller diameter projectiles simply do not have as much drag while passing through the targets tissue and consequently do not cause as much damage. Length to girth also affects stability while passing through intermediate barriers which is important for combat applications.

    I'm not sure why everyone thinks 6.5mm projectiles are magic and can have superior aerodynamic properties while also magically somehow causing "more damage" to the target than larger diameter less aerodynamically efficient projectiles...it's fantastical nonsense. Everything is a trade off and 6.8mm / .277 cal split the difference between the long and skinny (6mm / 6.5mm) vs. short and fat (7mm / 7.62mm) projectile designs. It's a middle ground that makes it more versatile which is exactly what you want for an intermediate fighting gun cartridge, but with proper load, it's also a great hunting cartridge.

    This is not a plug for 6.8 SPC being some end all be all cartridge. It's not. 6.5 Creedmoor and .308 vastly outperform 6.8 SPC at long range and still outperform it at medium range by a considerable margin. However for it's given application, 6.8 SPC has a better balance of exterior ballistics vs. terminal ballistics vs. platform compatibility / rel for an AR-15 frame size. Both 6.5 Grendel and 6.8 SPC significantly outperform the best 5.56 loads at any range within their usable span.

    https://ndiastorage.blob.core.usgovc...tl/Roberts.pdf

    https://ndiastorage.blob.core.usgovc.../Zhou19394.pdf

    http://www.frfrogspad.com/68spc.htm
    Last edited by win&legend; 01-06-21 at 10:45.

  5. #105
    Join Date
    Mar 2014
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    To anyone looking for 6.8 brass. I have 138 pieces of once fired 6.8 SPC brass looking for a new home. $.35 each. I've had a posting on the EE here in the past with other calibers and thought posting in a 6.8 thread might work. PM if interested.

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