View Full Version : 6.8 SPC
Voodoochild
10-02-06, 17:42
Can anyone school me on this rig. I have seen a couple of 6.8 SPC rigs in the picture thread but dont kno wmuch about them. Anyone want to contribute any info.
Can anyone school me on this rig. I have seen a couple of 6.8 SPC rigs in the picture thread but dont kno wmuch about them. Anyone want to contribute any info.
Its an AR that shoots 6.8SPC ammunition.
Voodoochild
10-02-06, 19:22
Wow that was so very informative...
What would you like to know specifically?
davemcdonald
10-02-06, 20:41
I'm sure somebody will come along that knows more but my peanut gallery version is it's a 5.56 casing necked up to something like a .243. This allows an even heavier bullet than the 75 and 77 grain versions that are popular in the AR platform. Call it a "quicker Jihadi-stopper". Supposedly it was designed so one could change the barrel and BCH on the current military personal weapon system and provide a more capable cartridge without going back to square one on the rifle. There have been some issues with the mag as the mil-spec mag has a deeper groove than is required by the heavier bullet. This makes the round less attractive to the military because they don't want to have to trade in several million magazines for mags with a slightly different spec. PRI, I think is the company that makes the current mag of favor for the 6.8 guys but I am hearing alot of talk about Cproducts also.
Hope this helps. BTW this is all purely conjecture, speculation and personal opinion on my part.
Dave
Zak Smith has written the most comprehensive and accurate article on the history, genesis, and development of the 6.8 mm SPC that I have yet publicly encountered: http://demigod.org/~zak/archive/sgn_68spc.pdf
First public discussion of 6.8 mm: http://www.tacticalforums.com/cgi-bin/tacticalubb/ultimatebb.cgi?ubb=get_topic;f=78;t=000512#000000
Mags are available from PRI, Barrett, and C-Products. Ammo is available from Hornady, Remington, and Silver State Armory.
6.8 mm offers significantly better terminal perfomance than 5.56 mm, especially in 16" and under barrels. 6.8 mm is an inherently very accurate cartridge.
After you have fully read the links above, feel free to ask any additional questions.
6.8 is very effective and effecient out of short barrels, but is fairly expensive to shoot. It's worth the extra money to me, and I'm getting a Dillon 650 to help the cause.
Actually the parent case is a .30 Remington (old woods hunting cartridge designed for semi-autos) IIRC. The case head is larger than 5.56 so if you ever look at a 6.8 bolt, there doesn't seem to be much steel surrounding the rim. Bt there must be enough because I don't hear anything about bolt failures.
Early velocity predictions were pretty ambitous, but I think things have settled down to around 2550-2600 fps for a 115 grain pill from a 16" barrel. Caliber is .277, you might as well call it the .270 Win LITE.
It does need proprietary mags.
The reason that I went with the 6.8SPC versus the 6.5 Grendel is because of the reason just stated. The 6.5 uses the 7.62x39 bolt which, according to everything that I have ever read, is very, very prone to bolt breakage due to the amount of material removed to accomodate the diameter of the casehead. 6.8 doesn't remove nearly as much material and is almost exactly the size of the .40 S&W casehead. The Grendel does have impressive ballistic figures though, so maybe you should look at that depending on your needs.;)
The 6.5 uses the 7.62x39 bolt which, according to everything that I have ever read, is very, very prone to bolt breakage due to the amount of material removed to accomodate the diameter of the casehead.
Tony Rumore and Marty ter Weeme have been using trimmed out bolts for years and years on the higher pressure 50AE, 440 Corbon, and 458 SOCOM.
Marty has only complained ONCE about bolt failure that I've seen.
Round counts are probably low, then again I suspect round counts on the 6.5 Grendels will be low too.
I will probably buy a 6.8 "tactical" model....
The Grendel offered, what I felt, was a tangible long range ballistic advantage.
If this is unimportant in the buying decision, the 6.8 looks like a FINE cartridge.
The Grendel offered, what I felt, was a tangible long range ballistic advantage.
If this is unimportant in the buying decision, the 6.8 looks like a FINE cartridge.
I couldn't have said it better
From what I have "READ" the bolts AA and Arne (http://www.competitionshootingsports.com/) are selling are patterned from the 7.62x39 but they are built up. In fact when I bought my kit from Arne he told me that the bolts he is selling are another progression from what AA sells, meaning they have been reworked even more.
Also, I bought the 6.5 for precisely the reasons SHIVAN said. Long range shooting. Better than 308 trajectory at 1000 yards and just a little less or equal power all along that flight path.
From what I can tell the only advantage offered by the 6.8 is better performance from short barrels out to 300 yards or so, after that the Mk 262 Mod 1 loads actually start performing better because they don't loose their energy as fast (better BC?)
I'm no expert, but this is what I get from what I have read.
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