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6.5mm or 6.8mm SPC?

Discussion in 'Rifle Country' started by JohnL2, Nov 19, 2006.

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  1. JohnL2

    JohnL2 Member

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    I know these two rounds are still relatively new. I just want something a step up from the ubiquitous 5.56mm "mouse round". Which is truly superior in performance?
     
  2. browningguy

    browningguy Member

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    I don't own either one, but the 6.5, as I recall, has somewhat superior ballistics.
     
  3. rbernie
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    rbernie Member

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    Inside of 300 yards, you'll not likely see a meaningful difference in trajectory or retained energy betwen the two. That means, for most of us, that we should probably just get the one we can get. That would most likely be the 6.8SPC.

    There are a bunch of barrel makers churning our 6.8SPC uppers across all price ranges, brass is available from several sources, and PRI makes solid reliable (if not a bit pricy) magazines that you can buy from a number of sources.

    The 6.5 Grendel, however great it may or may not be, is simply not being released fast enough by Alexander Arms to make it viable. The brass is hard to get, there are only two or three viable sources of barrels, there is only one source of mags that I know of that work, and so forth.
     
  4. CB900F

    CB900F Member

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    John;

    The Grendel may be new, but the 6.5 concept is hardly new. The 6.5 Swede has been around for a while now. Maybe even a while and a half, considering that it's now in it's third century. That's the 1800's, the 1900's, and now the 21st century.

    Must be a reason it's a keeper, huh?
     
  5. rangerruck

    rangerruck Member

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    6.5 swede or 6.5 grendel? the 6.5 swede is very old. the 6.5 grendel is not. either are far superior to the 6.8 go here;http://www.6mmbr.com/index.html
     
  6. Bigfoot

    Bigfoot Member

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    The reason the 6.5 Grendel is compared to the Swed is because the old 6.5x55 loadings that made it famous as a hunting cartridge are very similar to what the current Grendel does now. So unless Darwinism has made deer more bulletproof in this century than they were the last the 6.5 Grendel should be just as good. In fact it's also very close to the old, deadly 250 Savage and the early 257 Roberts loads.

    Yes at close range they are twins for defense. At least the gel tests say so.

    But for hunting the Grendel has it all over the SPC because the 6.8 is limited in bullet length/weight because with that long case length it's limited to short bullets. How many .277 caliber hunting bullets under 130 grains are there to choose from? And if there were I'll bet they were designed for the much higher 270 Win velocities.

    Since the Grendel bullets are longer/heavier they have way, way higher BCs and SDs which means better penetration and better velocity/energy as the distance increases. Also there are many 100-120 grain 6.5mm bullets to choose from which the 35 gr. case capacity favors. And.. you can load up reeaallyy high BC 140s if you want to hunt hogs etc.

    No real comparison for hunting.
     
  7. strambo

    strambo Member

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    For hunting or for a ballistics geek (me) the 6.5 Grendel would be better due to the superior BC and many more usable bullet weights up to 144gr. For a harder hitting AR at 0-300 meters with ammo a little more available and perhaps mags a little more reliable, the 6.8. I don't see either getting adopted by the military any time soon so that doesn't matter.
     
  8. Gewehr98

    Gewehr98 Member

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    The 6.8 was chosen for a specific reason.

    Zak Smith can fill you in, but the military did look at the 6.5mm bullet before settling on the 6.8 SPC. That .277" bullet has a good sectional density while still being short enough for the max powder capacity available, and still fit in an M16/AR-15 magazine well. Also, the 6.8 SPC runs on a necked-down and shortened .30 Remington case, with a smaller case head and case diameter than the 6.5 Grendel, itself an ever-so-slightly-improved 6.5mm PPC round. From what's out there in the information world, it appears the 6.8 SPC feeds better and is somewhat less fussy than the 6.5 Grendel.

    Myself, I'd prefer a compromise between the two, namely, a 6.5 SPC, which is a 6.8 SPC necked down that last .013" to be a true 6.5mm. Problem again is that you're limited by how long a bullet you can load before you intrude into powder capacity, so I'd probably try something along the lines of the 120gr Nosler Ballistic Tip, or 123gr Lapua Scenar. If those boattails are too long for the case, then I'd have to go with a flat-base bullet, with obvious long-range BC implications, probably closer to the 6.8 SPC's .277" bullet at that point.
     
  9. Bigfoot

    Bigfoot Member

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    Gewehr98 and Strambo, untill recently I had the same opinion but newer bullets have changed things. The Grendel is equal to the SPC at close range now.

    A cartridges terminal performance, especially if it depends on fragmentation instead of mushroom diameter depends on the construction of the bullets used. The current 6.5mm bullets wern't available when DocGKR (who conducted and evaluated the gel tests) decided that the .277 caliber bullets worked best. Here's the newest gel test with Doc Roberts doing the comparisons. Plus, this is the new 123SMK. Even though the 123SMKs performance is close to the best 6.8SPC bullet, the thicker jacketed SMKs have always had a length to fragmentation (neck length) a bit longer than others like the Hornadys. Buuttt.... Berger has a brand new 6.5mm 120 grain J4 (thin) jacket bullet out that should have a shorter neck, might even beat the Hornady 6.8, and like the 123SMK it has a BC close to .500.

    Gel tests: First the 6.5 Grendel tests with DocGKR himself doing the play by play and then his original 6.8 tests so you can be the judge.

    http://www.65grendel.com/forum/showthread.php?t=840

    http://www.tacticalforums.com/cgi-bin/tacticalubb/ultimatebb.cgi?ubb=get_topic;f=78;t=000512;p=8

    Remember that besides the 6.8SPCs early successfull bullet tests the reason it had promised better short range performancs was because it promised a 115 gr bullet at 2800 fps. Which now turns out can't be factory duplicated without pressure spike issues and lawsuit adverse corporations like Remington don't like like kabooms. This is why current factory 6.8 ammo is downrated to 2625 fps, a downrating of 175 fps. Significant IMO.

    Oh yeah one more thing. Wolf will soon be selling brass cased 6.5 Grendel ammo with SP bullets at typical Wolf prices, the preproduction ammo is being evaluated right now.
     
  10. rbernie
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    rbernie Member

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    Actually, there are a number of folks who are running 130gr hunting bullets in their 6.8SPC just fine.

    Barnes and Hornady make dandy 115gr hunting bullets designed specifically for the 6.8SPC velocities, and Sierra offers a 110gr ProHunter and a 115gr OTM.

    Don't need high BCs to hunt hogs. More to the point, a 140gr .264 stepping out at less than 2400fps from a 20" tube doesn't make much more of an impression on a hog than does a 130gr .277 moving at an honest 2450fps from the same barrel length.

    I'm not trying to insinuate that the 6.8SPC is the solution to whatever ails ya. It's not. I just can't stand to see it postulated that the laws of physics can somehow be magically bent by one chambering when compared to another.

    The 6.5 Grendel is designed to do one thing really well; long range trajectory via the use of slippery bullets. It willingly and openly sacrifices case capacity for a long bullet ogive. If LD is your thing, then the 6.5 Grendel hands the 6.8SPC its butt on a platter. But I defy anyone to come up with real world supporting data to show how a Sierra .277 130gr at a BC of .42 moving at a MV of 2450fps is inferior to a Sierra .264 140gr at a BC of .49 and with a MV of 2350. My data says that they're within a half an inch of each other in drop and drift (10mph crosswind) at 300 yards.

    And that's just not enough to base a decision on, in my opinion, if hunting medium/large thin skinned game is on the agenda. Nope - I'd rather make my choice based upon the economics and logistics of it all. Of what value is the chambering if brass, dies, commercial ammo, magazines, and barrels are all so tightly constrained in terms of availability?

    If the 6.5 Grendel were as available as the 6.8SPC, it'd be a horse race. But Alexander Arms has chosen a path that pretty much gives the playing field to the 6.8SPC camp.
     
  11. Bigfoot

    Bigfoot Member

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    But, they both have the same case capacity, 35 gr water. They actually push similar weight bullets to similar initial velocities. So it's more like having your cake and eating it too. Mmmmm cake. :)

    The real difference between these two is the available bullets and thier performance at the velocities that they were designed for. And the extra range with those bullets.

    Many of the old 250 Savage and Roberts shooters will tell you that with the velocity range that these two cartridges operate in the 100s drop deer faster than the 117s and 120s. The 6.5mm Grendel has 100s and 120s, lots of them, and most of them will perform well at these velocities.

    How many of those .277 130s are going to open up on deer at 5-600 fps less than 270 Win velocity? And there are all of four available .277 bullets in the weight range that a 35 grain case favors? The 6.5 caliber has 14 bullets (game bullets, not varmint)under 130 to choose from, and I only counted Barnes TSXs leaving out the Xs and XLCs. I probably missed a couple of others as well.

    Yes in the past the proprietary Grendel reamers, brass and dies were difficult to find. Not anymore. Dies and reamers are out there for sale now and you can even rent reamers now. Things change. The new inexpensive Wolf ammo seals the deal for me, it might not for everyone. That's fine.

    What I want is a short, fast swinging, 6 lb. scoped Kel-Tec SU-16 in 6.5G in the woods on yotes, deer and hogs. On those hogs the 140s provide deep penetration, the high BCs I mentioned are just a bonus. ;)

    With a 26 rd. AR magazine it will see double duty for defense.

    Edit: BTW your LR comparison between the two stacked the deck with the bullet weights and velocity. If using the 6.5mm 130 Scirocco at the same velocity you would get a 1.5" difference. Or use the 120 NBT (a better bullet comparison to the 270 130 due to the similar SDs) and get 2.5" less drop. Or use the 100 gr Partition and get 4" less drop. You see, with the 6.5mm bore you get a wide choice, that's my point. :D
     
    Last edited: Nov 20, 2006
  12. Langenator

    Langenator Member

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    FWIW, see the table on page 4 of this article, from Infantry Magazine two issues ago.

    At 300 yards, there's quite a difference in projectile energy between the 6.8 and 6.5, in the Grendel's favor-almost 250 fl/lbs from a 20" barrel, and over 100 ft/lbs from a 14.5".

    Unfortunately, the chart doesn't include bullet drop at the various ranges.
     
  13. Tony Williams

    Tony Williams Member

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    Considering that both rounds were developed with military applications in mind, the primary difference between them is that the 6.8mm was optimised for ranges up to 300m (which is really all you need in an assault rifle) whereas the 6.5mm was designed to work well in an assault rifle and to have a long-range performance good enough to match the service 7.62x51 M80 ball round.

    So while the 6.8 would be a good replacement for the 5.56mm, the 6.5 has the performance to replace both the 5.56mm and the 7.62mm.

    Tony Williams: Military gun and ammunition website and discussion forum
     
  14. HorseSoldier

    HorseSoldier Member

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    On paper, perhaps. In practice, you're still giving up something when you lose that extra 25-50 grains of bullet mass and milimeter or so of diameter from 7.62 to 6.5mm.

    In answer to the originally posted question on which is a better buy, I'd have to say it depends on a lot on application. The 6.8mm Rem SPC appears to be the better military service cartridge. I say this primarily because I see the 6.5mm Grendel round just answering a bunch of irrelevant questions for a service rifle -- i.e. great ballistics at 600-1000 meters means very little from a 4 MOA service rifle with iron sights or an AimPoint. If the cartridge gives up even one tenth of one percent in feeding reliability to get those ballistics it's just the wrong idea.

    The Grendel, however, is a great round for longer range shooting, when paired with a good weapon and optics, if that's what you're looking for.

    For shooting deer and similar sized game, flip a coin, unless you routinely shoot at deer from 4-800 meters. For tacticool factor -- same thing, flip a coin. For buying the next-big-military-thing ahead of Uncle Sugar . . . flip a coin, but neither will be entering service any time soon.
     
  15. Grendelizer

    Grendelizer Member

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    Go Grendel!

    Raw performance isn't the only criteria, as some have pointed out, but if that's what you're asking about, then look into the 6.5 Grendel.

    Basically, the 6.5 Grendel can do anything the 6.8 SPC can do, but the 68SPC can't do everything the 65G can do. The 65G can handle a wide variety of bullet weights and can always load stubbier bullets, but the 68SPC can't load sleek bullets like the 65G (at least not within the magazine-length limits of an AR).

    If the two start out at roughly the same muzzle velocity, then the higher ballistic coefficient bullets of the 6.5 Grendel will retain more velocity out to longer ranges. That means they will shoot flatter, drift less in crosswinds, and hit harder.

    For deer and hogs at standard hunting ranges, I wouldn't expect to see any practical difference. For larger game like elk and moose, the higher sectional density bullets of the 6.5 Grendel will offer more penetration potential through heavy hide, muscle, and bone. (This makes the 65G kind of like a 6.5x55 Swedish "Lite.")

    Regarding tactical performance, consider the following photo of gel test performance from the new Sierra 6.5mm 123gr MatchKing from a M4-style 14.5-inch Grendel carbine at 50 yards:

    [​IMG]

    If the 6.5 Grendel didn't show potential for performance in the tactical arena, wound ballistician Dr. Gary Roberts would not have posted on my forum that, "I have recommended to Jeff Hoffman at Black Hills to consider loading the 123gr SMK or the new 120gr Berger OTM, as well as a bonded barrier load like a Nosler Accubond or Swift Scirocco for the 6.5G."

    If Black Hills loads 6.5 Grendel as Dr. Roberts suggests, who knows if certain users might find it a suitable alternative to 5.56 Mk262?

    I don't know if you're hunting, target shooting, or interested in home defense, but for an all-around general-purpose intermediate cartridge, the 6.5 Grendel is "truly superior in performance."

    John
     
    Last edited: Nov 21, 2006
  16. rangerruck

    rangerruck Member

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    plus when measuring part for part, there are less changes needed to make an ar run on the grendel than the spc. also remember , they weigh a tad less. now for carrying a few bullets would be nothing. but humping several loaded mags, and several 100 more rounds in your ruck, you will feel that difference.
     
  17. Zak Smith

    Zak Smith Moderator Emeritus

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    FWIW,

    The original design goal for the SPC project was "200 fps faster than AK-47 ammunition from the same barrel length." I am pretty sure this does NOT mean 2800fps-- more like 2530fps (2330fps per wikipedia + 200fps), and the original loads were going 2635 to 2650fps.

    2800fps is a red herring created by Remington and serves only to confuse the debate.

    -z
     
  18. ECVMatt

    ECVMatt Member

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    I am sure they are both good rounds...

    However I got a 6.8 because it is much easier to find ammo for around here. I did not get an AR, but got a Remington 700 Tactical. I got is most for my wife and kids to have something fun to shoot. I ended up keeping it for myself. It is a great rifle and shoots very accurately out to 300 yards. That is all I need from this rifle. I load a 90grn HP at about 3000 FPS and it most certianly puts the hammer on coyotes and such. I see no reason why this would not carry over to other types of critters.

    I am going to get a 6.8 AR upper for my pre-cali ban AR. I really like the round.

    Matt
     
  19. High Planes Drifter

    High Planes Drifter Member

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    quote:
    If the 6.5 Grendel were as available as the 6.8SPC, it'd be a horse race. But Alexander Arms has chosen a path that pretty much gives the playing field to the 6.8SPC camp
    -------------------------------------

    Agreed. And the 6.8 has big green behind it. It looks like the 6.8 is finally starting to catch on and gain in popularity.
     
  20. Langenator

    Langenator Member

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    I think AA is making the same mistake Sony made with Beta, and Apple largely made with Mac...

    Hopefully the 6.5G becomes at least a cult favorite like the Mac, and doesn't go to the dustpile like Beta...
     
  21. ryoushi

    ryoushi Member

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    The 6.8spc is certainly a step up and truly superior in performance compared to the 5.56. Buy with confidence.
     
  22. Grendelizer

    Grendelizer Member

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    65G Hunting Photo

    A guy on my forum got a nice buck with his 6.5 Grendel. Just goes to show it's good for something besides punching paper at long range! ;)

    John
     

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  23. Langenator

    Langenator Member

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    Hell, the Swedes have been punching moose with 6.5mm rifles for over a century.
     
  24. Colt46

    Colt46 Member

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    I'll take the Grendel

    Supply is really short right now, but it's popular enough for Alexander Arms to keep busy. The 6.8 SPC has Big Green behind it. From an out of the gate enterprise that means a great deal. If Remington doesn't get enough interest they will cease production and leave the 6.8 to the same fate as the 6mm Remington, Etronix and their other white elephants.
    What I do like is their releasing it in a handy bolt action. A lightweight, easy recoiling, 130 or 140 grain bullet(either 6.5 or 6.8) would make a great rifle to have for large game hunting.
    However, I don't think the shooting public finds anything sexy about sub 3000 fps bullets and long term success of the 6.8 will be elusive.
     
  25. jonsidneyb

    jonsidneyb Member

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    6.5 I think is the easy answer. If there is very little difference up close...that is a push. The difference in long range capability of the 6.5 is a freebe.
     
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