6.8SPC vs 6.5 Grendel Info needed

[Desert_AIP]

That statement isn't true. There is very little difference between the 6.8 SPC and 6.5 Grendel out of a shorter barrel. Here are the energy stats out of a 14.5" barrel for both rounds.

Cartridge...Bullet....0...100..300 500 800 1000 yds.

6.8x43mm 115gr 1596 1282 803 489 271 215
6.5x38mm 110gr 1508 1293 936 664 396 297

At 100 yards, there's less than a 1% difference in energy between the two cartridges. But at 300 yards and above, the 6.5 Grendel pulls away and it's no contest.

http://www.thedonovan.com/archives/gunstuff/12_fa02.pdf

Those are VERY OLD stats for 6.8 SPC.
I don't think we've really seen that performance from the 6.5 out of short barrels either.
The case design has a lot to do with the 6.8's short barrel performance.
It's very efficient with transferring energy.
Most of the velocity of the round is generated in the first 8-10" of barrel.
The neck down PPC style case of the Grendel restricts the outflow of gasses somewhat. That is why longer barrel are preferred for the Grendel.

[aermotor]

IIRC, the 6.8 SPC is good out to about 300 yards. The 6.5 Grendel is good out to about 800 yards. Both shoot very well out of 16" barrels. The 6.5 Grendel is more accurate than the 6.8 SPC. The 6.8 supposedly has the ability to go through heavy walls like the 7.62 x 39. Evidently more so than the 6.5.

What do you mean when you say "good" in referring to their yardage? (6.8 good to 300 6.5 good to 800) If 5.56 is easily good to 400+ yards, the 6.8 has to at least be a few hundred more than that doesn't it?

[wash]

6.5 Grendel might be accurate out to 800 yards because of a high B.C. bullet.

6.8 SPC's velocity falls off faster but it is accurate, Bill Wilson just shot a 5.5" group at 500 yards. I think that was out of a 16" barrel but it could have been 18".

5.56 can group well out far but what are the terminal effects?

6.8 SPC with the right barrel and ammo is a good pig killer out to 300 yards. A pig is a lot tougher than a man.

Grendel might be more accurate at longer distance but how much energy is left?

So what's more important to you, 500+ yard accuracy or more knock down power inside of 300 yards?

Each has it's place, 6.5 Grendel does have more bullets but 6.8 SPC has a bunch of nice bullets and surely more to come. There will be brass case 6.8 SPC for $13.99 a box in a couple months (SSA), I think that compares nicely to Wolf 6.5 Grendel.

[thmpr]

Both are great cartridges... two different roles.

Brass and bullets are plentiful.

[jaymz]

Not again!

[ar15barrels]

6.8 SPC
6.5 Grendel

If you modify those searches to only show "available/in-stock", there's 9 options for 6.8 ammo that you can purchase today.
There are NO options for 6.5 ammo that you can buy today.

I'm just saying...

[jjperl]

Personally, I'm going with the 6.8 spc for my next build. I generally don't need to shoot anything out past 300 yds, so it suits my needs just fine. Plus the energy up close is pretty amazing.

On top of not needing to go past 300 yds, reliability is a key issue to me. The shape of the 6.8 spc cartridge looks as though it will cycle more efficiently than the 6.5G in a semi-auto rifle. That's just my opinion though.

[ar15barrels]

The case design has a lot to do with the 6.8's short barrel performance.
It's very efficient with transferring energy.

Let's not forget that the 6.8 feeds more reliably too due to it's gentler shoulder angle and more tapered case body which is much more similar to a 5.56 than the 6.5 case with it's sharp shoulder and blown-out case body.

[Desert_AIP]

Let's not forget that the 6.8 feeds more reliably too due to it's gentler shoulder angle and more tapered case body which is much more similar to a 5.56 than the 6.5 case with it's sharp shoulder and blown-out case body.

I read a similar statement from DocGKR a while back, but couldn't remember the technical details as to why.
Thanks Randall!

[ar15barrels]

I read a similar statement from DocGKR a while back, but couldn't remember the technical details as to why.
Thanks Randall!

AA recommends ramping the barrel and receiver more than M4 feedramps to improve feeding.