Quantcast
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

6.8 SPC vs. 7.62x39?

Discussion in 'Rifle Country' started by Carbon_15, Mar 15, 2005.

Thread Status:
Not open for further replies.
  1. Carbon_15

    Carbon_15 Member

    Joined:
    Jan 1, 2003
    Messages:
    922
    Location:
    South Carolina
    In glancing over the ballistics of the new 6.8SPC it looks like we have (at great expence) succesfuly reinvinted the wheel. Why is the 6.8 better than the good ol' 7.62commie?
     
  2. Kor

    Kor Member

    Joined:
    Dec 24, 2002
    Messages:
    774
    Location:
    Tucson, AZ
    1) Because it's newer, costs more, and is more tactical than that cheapo steel-case Commie round that you can buy for $80/case. :rolleyes:

    2) The 6.8mm bullet has a better ballistic coefficient than the 123gr .311 bullet of the 7.62X39, which yields a flatter trajectory and better downrange performance/terminal ballistics at ranges in excess of 4-500 meters.

    3) The 6.8mmSPC cartridge was designed to allow existing M16's and M4's to be readily adapted to fire it without modifying existing M16 magazines - IIRC, all that needs to be swapped are the barrel and bolt, standard 30-rd 5.56 mags will hold 24 or 28(not sure) rounds of 6.8mm.
     
  3. ks_shooter

    ks_shooter Member

    Joined:
    Jan 3, 2003
    Messages:
    97
    Location:
    Paola ,KS
    About 20% more energy at the muzzle and about 33% more energy at 200 yards. Because of a better bullet BC, it holds its energy better, drops less and drifts less in the wind. No magic. Its not "Thor's Hammer" :rolleyes: . Just an honest, significant improvement. It also has a straight case body so you don't need those stupid curved commie mags :)

    The 7.62x39 lethality could be improved with a better buller design. I think the commie round is known for uncomplicated wounds if bone is missed. At 2400 fps with a stubby bullet its hard to get tumbling or fragmentation. A good soft-point would be an improvement, but there's that problem of the Hague (sp?) convention.
     
  4. Fumbler

    Fumbler Member

    Joined:
    Oct 28, 2004
    Messages:
    1,508
    Location:
    Rocky Mount, NC, USA
    They should have made it with a rebated rim so they wouldn't even have to change the bolt.
     
  5. Master Blaster

    Master Blaster Member

    Joined:
    Dec 26, 2002
    Messages:
    4,887
    Location:
    Delaware home of tax free shopping
    Its very accurate and you can hit something smaller than a 9 inch circle at 100 yards, Unlike the commie round, which has to be the most innaccurate rifle round ever developed in the 20th century.
     
  6. Lonestar.45

    Lonestar.45 Member

    Joined:
    Sep 3, 2004
    Messages:
    1,077
    "Unlike the commie round, which has to be the most innaccurate rifle round ever developed in the 20th century."

    If you can't hit a 9" circle at 100 yds with 7.62x39, then I'd say there's a problem with either the gun, the quality of the ammo, the shooter, or all three. :confused: I can do 2-3" all day long with my SKS open sights, and I've seen AK's that can do the same thing. I think the round gets a bad rap on accuracy because guys go buy the cheapest possible dirty 30 year old ammo that's been stored in an outhouse in Romania and shoot it through guns made by communist slave labor.

    The round itself, when shot through a quality gun (like a CZ 527 Carbine), with quality ammo, is just as accurate as anything out there. That said, the 6.8spc is ballistically superior to it, with better bullet design, giving it longer range accuracy and energy.
     
  7. Zak Smith

    Zak Smith Moderator Emeritus

    Joined:
    Dec 24, 2002
    Messages:
    9,037
    Location:
    Fort Collins, CO, USA.
    Comparison of some typical loads:
    Code:
    _Bullet_           _BC_ _MV_         0     100     200     300     400     500     600 | YARDS
    223 77OTM         0.362 2670 >   -2.60   -0.00   -3.28  -13.66  -32.72  -62.44 -105.35 | drop (inches)
                                      0.00    0.92    3.86    9.12   17.05   28.04   42.51 | wind (inches)
    6.8 110VMAX       0.370 2630 >   -2.60   -0.00   -3.44  -14.16  -33.74  -64.16 -107.94 | drop (inches)
                                      0.00    0.92    3.86    9.10   17.00   27.92   42.26 | wind (inches)
    7.62x39 Fed       0.289 2300 >   -2.60   -0.00   -5.86  -22.69  -53.83 -103.65 -177.36 | drop (inches)
                                      0.00    1.46    6.20   14.84   28.02   46.23   69.43 | wind (inches)
    
     
  8. Zak Smith

    Zak Smith Moderator Emeritus

    Joined:
    Dec 24, 2002
    Messages:
    9,037
    Location:
    Fort Collins, CO, USA.
    Incorrect. Please consult the 6.8SPC FAQ (see below). USGI M16 mags do not work.
     
  9. Bigfoot

    Bigfoot Member

    Joined:
    Feb 5, 2004
    Messages:
    708
    Location:
    Oregon
    "I think the round gets a bad rap on accuracy because guys go buy the cheapest possible dirty 30 year old ammo that's been stored in an outhouse in Romania and shoot it through guns made by communist slave labor."

    That's some of the better ammo. I've had some that must have been stored UNDER the outhouse. Yes, it shot like crap.
     
  10. beerslurpy

    beerslurpy member

    Joined:
    Nov 8, 2004
    Messages:
    4,438
    Location:
    Spring Hill, Florida
    I paid under 80 bucks for 1000 rounds of uly match (nipple round) and it is clean and accurate. All of my bullets go into a 3" circle at 100 yards and I am using a scope with a 3MOA dot. That is what happens when you pay 550 for a good AK instead of expecting bushmaster accuracy from a 250 dollar weld job made in a barn in hungary.

    Spend 700 dollars on an AK (an insanely high amount) and you will get a gun that is every bit as accurate as good AR15 (good luck finding one that cheap) out to 300-350 yards. The only downside to the 7.62 round is that beyond 350 yards it is impossible to hit anything with it due to bullet drop. The 6.8 seems to combine most of the positives of the 7.62 (good momentum and better sectional density) with most of the accuracy of the 5.56. The AK is probably overkill in terms of barrier penetration, so its not really a big loss to get the extra accuracy.

    The downsides of the russian round are only bad if you are fighting at long ranges with only batallion level snipers. If at least one person in every squad had something in 308 or 3006, there would be no problem from the weak long range performance.

    That being said, I cant even find a 300 yard range around here, so my 7 cents a round AK is definitely more than enough gun for my satisfaction. I also live in a relatively hilly and populated area, so the odds of me having to take > 300 yard shots in a SHTF situation are slim. And I have a scoped 7mm rem for long distance shooting (again, wishing I had some long distance ranges here).
     
  11. Zak Smith

    Zak Smith Moderator Emeritus

    Joined:
    Dec 24, 2002
    Messages:
    9,037
    Location:
    Fort Collins, CO, USA.
    A Honda Accord will get you to work, but it's no BMW M3.

    First-round hits on steel at 500 yards are pretty easily doable with 5.56 or 6.8.

    -z
     
  12. Malamute

    Malamute Member

    Joined:
    May 12, 2004
    Messages:
    2,980
    Location:
    Rocky Mts
    First I heard of the 6.8, they were wanting a round that would have as MUCH range as the 7.62x39, the 5.56 doesn't hold up well in mountainous areas at long range, and being a bit sensitive to wind. They were being outranged by 7.62x39 rounds in those conditions. I'm not sure how the bullet falls so much it's impossible to hit with it past 350 yards, most guns have sights that adjust to longer ranges, so this isn't an issue unless one isn't able to judge range. Still, getting within 100 yards of the proper range setting will get you pretty close. If you hit low, add another notch up on the sight. I've plinked at rocks etc out to 500 yards with 7.62x39's, and with the sights set to that range, they hit right on POA.

    The stamped receiver Kalashnikovs aren't the best shooting guns. A milled receiver gun is another story. Cheap Wolf ball ammo did 2 1/2" @ 100 yards with no problem. This with Valmet type sights.(peep rear)

    BTW, those funny looking curved magazines are a result of the taper in the 7.62x39 case, and one reasons for the reputation for reliability. The taper helps feed and extract easier than a straighter case.

    As I understand it, the 7.62x39 round performs pretty similar to the 7.62 Nato round in terminal performance. They tend to swap ends in soft targets. Both seem to have improved wound potential when they have a steel jacketed bullet, as they tend to be more brittle, and hence, fragment more redily. I've seen various tests that show sometimes conflicting info. If I'm mistaken on this point, anyone with more information on the matter feel free to correct me.


    I guess I'm in the camp of "they are reinventing the wheel" with the 6.8. They already have 7.62x39 AR's, wonder why they didn't just use those conversions?

    Having said all that, we (they, US Military) already have very good medium to long range guns, the M-14. I've seen pictures of scoped H-K G3's being used in open areas also. Having lived in fairly open country most of my life, I like having a gun that can shoot way out there. The reason given for going to the 5.56 was controlability in full auto fire. If we don't shoot full auto and we don't have the controlability problem. Don't need all the extra ammo either if not using it up on full auto shooting. Let the belt fed guns take care of that job.
     
  13. Zak Smith

    Zak Smith Moderator Emeritus

    Joined:
    Dec 24, 2002
    Messages:
    9,037
    Location:
    Fort Collins, CO, USA.
    Let's look at the data:
    Code:
    >> 7000 elevation, absolute drop (identical sight over bore)
    _Bullet_           _BC_ _MV_         0     100     200     300     400     500     600 | YARDS
    M855              0.324 3100 >   -2.60    0.00   -1.64   -8.25  -20.73  -40.18  -67.97 | drop (inches)
    XM193             0.243 3254 >   -2.60    0.00   -1.45   -7.91  -20.62  -41.25  -72.00 | drop (inches)
    7.62x39 Fed       0.289 2300 >   -2.60   -0.00   -5.45  -20.81  -48.43  -91.27 -152.96 | drop (inches)
    
    >> Wind deflection, 10mph 90 degree
    M855              0.324 3100 >    0.00    0.68    2.80    6.55   12.12   19.76   29.75 | wind (inches)
    XM193             0.243 3254 >    0.00    0.86    3.58    8.49   15.94   26.41   40.45 | wind (inches)
    7.62x39 Fed       0.289 2300 >    0.00    1.17    4.91   11.61   21.69   35.54   53.44 | wind (inches)
    
    Hey, it looks like M855 has less than half the drop and 45% less wind drift than 7.62x39 at any range out to 600 yards.

    Try again?

    The trajectory of 6.8SPC is superior to 7.62x39; it happens to be almost identical in drop and wind drift to 168gr 308 or 75-77gr 5.56mm. 6.8's terminal effects are vastly better than anything 5.56 or 7.62x39 can offer.

    -z
     
  14. cracked butt

    cracked butt Member

    Joined:
    Jan 3, 2003
    Messages:
    6,986
    Location:
    SE Wisconsin
    Thanks.

    I am now wiping what was my late night snack of ramen noodles off my monitor screen. :p


    I have a friend who has one of the newer CZ bolt actions chambered in 7.62x39 and from what I've seen, its very accurate.
     
  15. Malamute

    Malamute Member

    Joined:
    May 12, 2004
    Messages:
    2,980
    Location:
    Rocky Mts
    The trajectory issue is moot unless you can't adjust your sights. They will all do the job of gettting to the target with the sights set to anywhere near close to the range. Flatter trajectory helps, but they all will do.

    The wind drift may indeed be less of an issue that they were saying, I was relating what I'd read when first hearing of the 6.8. I've heard about the wind problem with the 5.56 for a long time, from target shooters, varmint hunters, and soldiers.

    I'm not saying the 7.62x39 is necesarily better, just covers most of the same ground, and is already available.

    I would still prefer a 7.62 Nato to any of the smaller rounds. Just me.
     
  16. Zak Smith

    Zak Smith Moderator Emeritus

    Joined:
    Dec 24, 2002
    Messages:
    9,037
    Location:
    Fort Collins, CO, USA.
    No way. Trajectory is absolutely not moot.

    If you're shooting on a known-distance range at even intervals, I agree that you can dial your sights up and down (or your optic), though iron sights will be limited by their adjustment quantum (typically 100 meters for AK sights).

    However, when you're shooting at unknown arbitrary distances, the flatter shooting cartridge has the advantage because ranging errors cause fewer misses.

    At any range, 7.62x39 is dropping at over twice the rate of M855:
    Code:
    >> Drop rate inches per yard
    M855              0.324 3100 >    0.05    0.01   -0.04   -0.09   -0.16   -0.23   -0.32 | drop per yard (inches)
    XM193             0.243 3254 >    0.04    0.01   -0.04   -0.09   -0.16   -0.25   -0.37 | drop per yard (inches)
    7.62x39 Fed       0.289 2300 >    0.06   -0.01   -0.10   -0.21   -0.35   -0.52   -0.72 | drop per yard (inches)
    
    This basically means that for the same target area, the M855 can "tolerate" over twice the ranging error of 7.62x39, and still get hits.

    6.8SPC was designed to have dramatically better terminal effects from 0-300 meters with an acceptible long range trajectory, while running reliably in an M4 platform.

    -z
     
  17. rbernie
    • Contributing Member

    rbernie Member

    Joined:
    Jan 21, 2004
    Messages:
    20,450
    Location:
    Norra Texas
    This statement bothers me a bit, if only because I believe that the terminal effects are largely governed by the bullet construction and not by the caliber of the chambering that shot it. What I hear you saying, presuming that you have seen gelatin tests of all three, is that the 6.8 was loaded with a bullet that had better terminal performance. That's wonderful, but that's also an issue of what's loaded with what. I have no doubt that you could load any of these calibers with a bullet of a design such that they would all give reasonably similar performance in ballistic gelatin.
     
  18. Malamute

    Malamute Member

    Joined:
    May 12, 2004
    Messages:
    2,980
    Location:
    Rocky Mts
    Ok Zak, it sounds like you have a tremendous amount of theoretical knowledge. You've done your homework. Bravo.

    In my experience shooting in the field, I find it is not hard to make hits with a 7.62x39 at various unknown ranges out to 500 yards.

    I'm pretty indifferent to the 6.8 in particular, and the m-16 platform in general. Good for you if you like it and are the champion of the 6.8. I just don't care enough about it to argue about it.

    I still prefer a 7.62 Nato round. Have a nice day.
     
  19. Master Blaster

    Master Blaster Member

    Joined:
    Dec 26, 2002
    Messages:
    4,887
    Location:
    Delaware home of tax free shopping
    You know if the question had been 6.8 spc vs. 30-30 win I would be reading how terrible and old fashioned the 30-30 is and how unsuitable it is as a military round compared to 6.8 SPC, 5.56 nato, .308 nato, 30-06, or 5.56 russian, or any other military round in use today. 30-30 is an old obsolete marginal performer would be what the Ubber commandos here would be writing.

    Yet somehow when the topic of 7.62X39 round comes up its an ubber zombie killing round that vaproizes tanks at 600 yards, and it the best round that was ever devised. This is despite the fact that the soviets who developed the round only ever considered it to be a close range intermediate cartridge, AND THEY Abandonned it in favor of a 5.56 round 20 years ago.

    Even the lowly .30-.30 win outperforms 7.62x39.

    The ammo I bought for my one AK is wolf and barnul, it didnt come from under an outhouse, Like I said all the aks I have seen and shot are 9" 5 shot groupers at 100 yards. I keep reading about all those ubber accurate $1000+ custom AKs that can do 1" for 3 shots at 100 yards, but the 2 customs I see at my club can do 5" sometimes on a good day. Must be why no one uses aks in 7.62X39 for competition.

    JMHO YMMV
     
  20. Zak Smith

    Zak Smith Moderator Emeritus

    Joined:
    Dec 24, 2002
    Messages:
    9,037
    Location:
    Fort Collins, CO, USA.
    I have seen gel tests of all three. 5.56 and 7.62x39 are available on http://www.ammo-oracle.com , the best terminal ballistics information source on the web. I don't know if any 6.8 data is there yet, but there was a .mil powerpoint presentation leaked a while back which contained a lot of 6.8 data. The best terminal performer for 5.56 is the 75gr Hornady bullet or the 77gr Nosler bullet, neither of which is as good as the 115gr OTM 6.8 offering. You do have a point that I haven't seen extensive tests of non-military-loadings of 7.62x39. These have probably been dismissed because of the trajectory issue. They might be out there somewhere.

    Malamute, being refuted with data at every turn, resorts to ad hominem insults. If you'd like to put 7.62x39 against 6.8 in a practical rifle test, come down to our monthly precision rifle field match in Raton (details in the competition forum).

    -z
     
  21. Onslaught

    Onslaught Member

    Joined:
    Jan 3, 2003
    Messages:
    1,006
    Location:
    Georgia
    Zak's knowledge is a TAD more than "theoretical". He's an AVID Ar15 collector and shooter, and one of the PIONEERS of reloading for the 6.8 SPC...

    For someone who doesn't like the AR15 platform or the 6.8 enough to argue about it... :scrutiny:
     
  22. SpookyPistolero

    SpookyPistolero Member

    Joined:
    Jun 26, 2004
    Messages:
    934
    Location:
    Central Kentucky
    Hear, hear!

    I would be slow to bash the cartridge or Zak's knowledge of it. I'd say he's forgotten more about the relative ballistics of these cartridges than I will ever know.

    I am a proponent of the AK and the 7.62x39, and will be for a long time, but can still see the value of this cartridge. It looks to be, in my eyes, the best small arms cartridge we have seen yet. It seems the last test would be how it rates, in the field, as a man stopper. I imagine it will do quite well.

    The only disadvantage is the cost at this time, and I don't know enough about the ammunition industry to guess when prices will drop. That's why I am sticking to my 7.62x39, 1000 rnds for $80. That equals lots of practice for a poor college student. The cartridge suits my 'needs' well. However, those with more specialized needs would almost certainly be better served by the 6.8.

    -Spooky

    (PS- I intend to forgoe both cartridges and switch to .308 if my Saiga ever arrives...)
     
  23. Zak Smith

    Zak Smith Moderator Emeritus

    Joined:
    Dec 24, 2002
    Messages:
    9,037
    Location:
    Fort Collins, CO, USA.
    Cost and availability are big problems with 6.8SPC ammunition right now- there's no denying that.
     
  24. LeonCarr

    LeonCarr Member

    Joined:
    Mar 20, 2003
    Messages:
    3,817
    Location:
    At The Range
    Not to sound morbid, but have there been any confirmed kills with the 6.8 SPC? How did it perform? Have any actually been used in combat, ie Iraq or Afghanistan, that anybody knows about? For right now, it seems like it is THEORETICALLY better than the 5.56 or the 7.62x39, but it is still just academic until somebody gets shot with it, witness statements on its performance are written, and autopsies are performed.

    Just my .02,
    LeonCarr
    P.S. I have a milled receiver Bulgarian AK that shoots five shot, two inch groups off of sandbags at 100 yards with Wolf ammo, so I know of at least one decently accurate AK :).
     
    Last edited: Mar 16, 2005
  25. Mike Hull

    Mike Hull Member

    Joined:
    Feb 15, 2004
    Messages:
    322
    Location:
    Cottonwood, AZ
    Selective memory is a wonderful thing. ;) :D

    Agreed, and people have been badmouthing the 30-30 for decades as a hunting round, at least till TC put it in a pistol. I'm still scratching my head over how, all of a sudden, a round that supposedly isn't even good for deer, in a rifle, is suddenly transformed in a pistol to be a superior hunting round.

    MB, there's no rationallity to the whole thing. Don't even try to figure it out. ;) :D
     
Thread Status:
Not open for further replies.

Share This Page