How does the 6.8SPC cpmpare to the 7.62 X39?

[TLHelmer]

In terms of power and accuracy?

That title should read compare!

[nedrgr21]

THR has a good thread on it (is this ok to mention). I think the 6.8 is very similar to a 243 using a thinner case if that's an easier analogy for ya. Accuracy for 7.62, like any other cartridge, is more dependent on the weapon than the cartridge.

[DonD]

Based on the ballistics I've seen in magazine reports, the two guns are quite comparable power wise. In this case, I'm comparing the reported ballistics of the 6.8 to chronograph readings I get in my 18.5" barreled Ruger Mini30 (7.62x39) using Fiocchi ammo. It goes 2475 fps with a 123gr slug for 1674 ft lbs. In most cases, a good AR will outshoot a Mini and is far more accurate than a typical AK.

Remington's catalog shows the .243 running around 2000 ft lbs, not a huge difference but it's there. Don

[EL COLONEL]

Closer to a 270 not 243.

[vafish]

Closer to a 270 not 243.


I think he was comparing energy and velocity figures, not caliber.

6.8 SPC uses .270 diameter bullets.

6.8 SPC fires 115 gr bullet at 2,800 fps for 2,000 ft lbs of muzzle energy.

.243 Winchester fires a 100 gr bullet at 2,960 fps for 1,945 ft lbs of muzzle energy.

.270 Winchester fires a 130 gr bullet at 3,050 fps for 2,685 ft lbs of muzzle energy.


So the 6.8 is much closer velocity and energy wise to the .243 than it is the .270.

7.62x39 fires a 123 gr bullet at 2,365 fps for 1,527 ft lbs of muzzle energy, so the 6.8 is quite a bit faster and harder hitting.

[nedrgr21]

::thumbsup::

I'll add the 6.8 has a slightly bigger diameter, but the .243 has a higher sectional density for ~100 gr bullets - pick your poison.

[DonD]

Not trying to be difficult Vafish but where did you get 2000fps for the 6.8mm? Remington's catalog says 2625fps for the 115gr slug. Don

[vafish]

Not trying to be difficult Vafish but where did you get 2000fps for the 6.8mm? Remington's catalog says 2625fps for the 115gr slug. Don


2,800 FPS and 2,000 ft lbs of energy is what I said.

I've seen numbers all over the place for the 6.8 with 115 gr bullets, anywhere from 2,400 to 2,800 FPS.

The higher velocities are generally with 22"-24" barreled bolt action guns and the lower velocities with shorter barrels on AR's.

[PlasticGuy]

Comparing the 6.8 and the 7.62x39 out of 16" barrels (apples to apples), you get relatively similar numbers:

6.8 SPC runs around 115 grains at 2550 fps
7.62x39 runs around 123 grains at 2350 fps

I don't think anyone or anything would be able the tell the difference from being shot with each of them based on power alone. The three biggest differences for me are barrier penetration, terminal effects, and ammo cost and availability. The 7.62x39 is a much better penetrator with currently available loads. The 6.8 could be as good or better, but the loads that would allow that are not currently made (or at least not sold to civilians). However, the loads for the 6.8 are more likely to tumble and fragment than the 7.62x39, making it more terminally effective on unobstructed torso hits. Ammo cost and availability is the real killer right now. You can find 7.62x39 ammo anywhere in the world, and tends to run $4-$5 per box in this area. The ammo for the 6.8 is difficult to find and 2-3 times more expensive.

So far I've opted to stick with the 7.62x39 for my mid-power cartridge. For my purposes, the greater availability and lower cost combined with better barrier penetration outweigh the potentially better terminal effects of the 6.8 SPC. That may change in the future, but that's where I stand right now.

[TLHelmer]

Thanks guys!