6.8x43mm SPC Cartridge for Urban Warfare CQB and Short-to-Medium-Range Sniping

Defense Review ^ | 11/30/06 | David Crane

[Neo-Luddite]

"just aren't any modern semi-auto rifles in that caliber"

Never shot one, however: cobb50.com has an .06 ar varriant.


I'm waiting on someone to offer a GOOD out of the box shorty m-1 again with a sythetic stock and rail setup.

Box fed mags for any semi-auto .06 would cost too much.

Until then I'll make do.

I'm not completely anachronistic, I've got a mini(mal)-14 for close quarters.


There is lots of special purpose .30/06 around that is still legal. And, with an adapter, any .06 can shoot .308 in a pinch. So during post shtf shopping sprees you can grab both.

[Radio_Silence]

Found this article:

http://www.globalsecurity.org/military/systems/ground/m8-oicw.htm

From the article:
On 31 October 2005, the XM8 program was formally suspended, "pending further US Army reevaluations of its priorities for small caliber weapons, and to incorporate emerging requirements identified during Operation Enduring Freedom and Operation Iraqi Freedom. The Government will also incorporate studies looking into current capability gaps during said reevaluation.

"Capability gaps" is the key phrase. Another way of saying it would have been the army didn't care for a repackaged G36 that didn't have the same level of commonality of parts that the SCAR-L and H platform enjoys.

I can't find the link on the current status of the SCAR but am 99% sure it's the winner.

[ASOC]

Lets look at some numbers for the 6.8 SPC

When factory loads are fully developed, an 18" barrel should shoot the 115gr OTM at about 2750fps; the 16" barrel at about 2650fps; and a 12" barrel at just over 2500fps.

The BC of the 115gr Hornady is 0.340.[2] The BC of the 110gr VMAX is 0.362.

And then the 7.62x39 comblock round (hat tip to Chuckhawks)

The Remington factory load starts a 125 grain PSP bullets at 2365 fps with a muzzle energy of 1552 ft. lbs.

So - would loading the 7.62x39 with 115gr bullets give us the 300 fps difference (16in bbl) to make the result essentially the same? I am trying to round up some 7.62 115 gr BTHP to see they load OK in the x39 cases. Be the cheapest conversion I have ever made....

[Radio_Silence]

You're way, way ahead of me.

In theory it would seem that you are correct although I'm not sure how the different case dimensions and powder types will affect burn rate and the subsequent pressures you will achieve.

I'd be interested to know how it comes out. I'd also be interested to know how the two rounds compared in terms of accuracy.

Let me know if you are able to pull this off.

[absolootezer0]

just traded my .30-06 for a .308, altho my -06 was an awesome shooter, it was too small to be able to comfortably shoot from a bench all day.
.308 shoots the same bullet, just slower. if you reload, you can use the same powder and bullets.. saves on having to buy a bunch of different stuff.

[Jack Black]

The Russians replaced their .30 with a 5.45mm, not a 5.56mm round. It's a .21 caliber, in US terminology.

[ASOC]

Yup, I figure 115gr x 2300+ fps will give pretty much the same result. And the brass is a *lot* cheaper!

[Jack Black]

The other alternative to the 6.8 Rem SPC doesn't have as big a company behind it but may be a better round. That is the 6.5mm Grendel, developed by Alexander Arms who also designed the Beowolf .50.

Here is a blog with a write up on it: Airbone Combat Engineer's Blog write up of Grendel 6.5mm

Here is another one from Defense Review.com

They say in part: Interestingly, the 6.5 Grendel (6.5mm)/.26 Grendel is itself reportedly garnering a fair amount of positive attention from U.S. Special Operations forces, at the moment. From everything DefenseReview has seen, it's a very impressive cartridge. The 6.5 Grendel has a superior ballistic coefficient and thus superior long-range trajectory characterstics to the 6.8x43mm SPC/6.8mm SPC, past 500 meters. The 6.5 Grendel (6.5mm)/.26 Grendel bullet should also work quite well at CQB (Close Quarters Battle) range (if not quite as well as the 6.8mm SPC), especially if designed with an air pocket towards the tip like on the Russian 5.45x39mm bullet. Hopefully, an armor-piercing/armor-penetrating (AP) version of the 6.5 Grendel featuring a tungsten or tungsten carbide core will also be developed. DefenseReview is interested to know the amount of felt recoil that the 6.5 Grendel generates. For CQB applications, weapon controllability on full-auto is of primary importance--right up there with weapon reliability. While engaged in dynamic CQB in urban environments, our operators have to be able to get hits on hostile moving targets, fast.

Here is the manufacturers link: Alexander Arms grendel home page

The short squat one is the Grendel. The more traditional shaped one is the 6.8 SPC.

[P8riot]

I like the .50 Beowulf upper on my AR. Uses AR Mags too (at roughly half the capacity). But I'm really an AK guy.

[rellimpank]

--and I should know this but don't--is the 5.45 mm also dimensionally sufficiently similar to the 5.56mm so that in a pinch it may be fired in the 5.56mm chamber but not vice versa?

[Jack Black]

No. That's not possible. I think it would cause a catastrophic malfunction. I've heard of old Soviet and US ammo being interchanged in WW2 but both were the same diameter bullet. Not sure if that's a true story or an old wives tale, but the 5.45x39 would neither chamber nor fire in an AR platform and ditto for the reverse.

[thinkthenpost]

Lot's of talk about the Grendel. I don't think anything with that straight a walls will be used. The 308, 223 and SPC all have some taper, as well as the 50BMG and 30-06. I just seriously doubt a straight wall improved cartridge will be adopted by the military.

I have alway wondered with all the talk about the Grendel and the better ballistics of the 6.5 why the SPC is 6.8? I've read that the case was loaded with different sized bullets and I have the impression the 6.5 was one of the tested chamberings so how was the 6.8 settled on? makes you say Hmmmm.

[eXe]

Yeah from what I hear in town they also make some very good M855 556 as well.. I will have to stop in there one day and see if I can buy from them or if they even sell to the public in person or only mail order.

[rellimpank]

--thanks--I did find a dimensions website indicating the shoulder dia of the 5.45 to be bigger than the 5.56--IIRC, the Russian heavy machine gun (12.7mm or .51 cal??) can chamber .50 BMG---

[rellimpank]

--checking them out this pm--

[Armedanddangerous]

Nope, wont work..

[rellimpank]

--thanks --did a search after posting and got the dimensions--

[looscnnn]

I see them eventually moving back to the .308. They are moving up from the .223 to have a "much better round" for the listed uses. I can see a few years down the road they will state that they are going to go back to the .308 for a "much better round" for such and such.

Even if they don't, the .308 is not going to go away. Look at the 30-06, it has been out of military service for 40+ (?) years and is still readily available.

[ctdonath2]

Not really. The term does not necessarily preculde short ranges; actually under 100m is the norm. Precision is the issue, not distance.

The head-scratcher is that if you've got time to be that precise, the right tool (7.62 Win) is preferable - not some relatively underpowered thing. Jack of all trades, master of none...

[ctdonath2]

The 6.8x43mm Special Purpose Cartridge (SPC) ... a much better answer for urban warfare and CQB (Close Quarters Battle) than the 62gr 5.56x45mm NATO round, and a much better short and intermediate distance sniping round than the 77 gr. 5.56mm round

So how does it compare to the 77gr for CQB? Seems the author is picking & choosing his comparisons. If just switching to 77gr solves the CQB problem (relative to the 6.8) then the urgency for a new caliber diminishes.

Just want a fair comparison of numbers.