6.8SPC vs 6.5G

10" barrel shooting deer and hogs out to 250 yards. Is there even a distinct edge one has on the other?

At that distance, no. Some will say that the 6.8 does better in a shorter barrel, which isn't really true at carbine lengths. At 10", it may have some bearing. I'm not familiar with how they compare in a barrel that short.

The rounds themselves are very similar in what they will do inside 200 yards, after that advantage Grendel due to higher BC bullets available. The Nosler 6.5mm 129gr accubond is a wild card in this being a bullet that has a high BC and expands at 1300fps and up. There are reports of it expanding at 350 yards from 12.5 inch barreled SBRs. Plus the higher BC with the retained velocity will put more energy on the deer or hog.

I am debating this right now. If my math and assumptions are right you could have full expansion out to 450 yards

I would pick the bullet you want. For some odd reason I like nosler

No much difference between the two out to 300 or 350 yards with shorts barrels, then the better bc of the grendel holds more energy. Grendel seems to really kick butt with a nice long barrel. I was on the fence also, but went with the 12.5" 6.8 because i dont shoot out past 300 yards! Flip a coin. Still thinkng about building a grendel also.

Choose the cheaper one to shoot

Just ran through quickloads the Grendel 129gr Nosler at same load I am using in the Grendels shows 2124fps from a 10 inch barrel. The 123gr Hornady shows using the accepted max load of 8208XBR shows 2132fps. Note different powders but the loads I am running in Grendels with 22 and 24 inch barrels.

In reality would expect velocities close to those when running a can on the 10 inch barrels.

One issue I have with 6.5g short barrels is price. They are proud of them

Alexander arms has a 16in for 200ish that looks tempting

If you're not going to roll your own, keep ammo availability in mind. For instance, Midway has 17 listings for 6.8, only 5 for 6.5. Grendel will also be more expensive to shoot if you're not hand-loading.

This was the deciding factor for me. And on top of that if I plan on shooting more than 250 yards I wont have the 6.8 in my hand anyway.

Just bought a bunch of the federal xm6.8 90 grain protected bonded softpoint that was on sale at palmetto state arms for 9.99 a box. Sale ended at noon. Good 250 yard deer and hog factory ammo.

I don't know about 10" barrels but in a 12.5" the 6.8 is pushing factory Hornady 120gr SST's at 2410fps. Can you run the Grendel in a 12.5" to compare apples to apples. IIRC in 16" barrels and shorter the 6.8 edges out the 6.5 Grendel until 250 yards or so.

Okay, everyone looks at the difference between the 6.8 and 6.5. What about the 7.62x39 between the the other two?

I don't know about 6.5.
My 6.8 dropped 6 inches at 200 yards shooting ssa 110 grain.
I couldn't get use to how it shot so I sold it and just shoot my 270.

The 6.8 max SAAMI pressure is 6740 PSI higher than the Grendel pretty much negating the 10% more powder volume. Take that into account with the higher expansion ratio of the larger bore and shorter bearing surface of the bullets commonly used in them the 6.8 usually has a higher muzzle velocity in the same barrel. Where the Grendel makes that up is with sectional density and BC. Bullets of the same construction the higher sectional density ones will penetrate more. There have been enough discussions of BC on here not to really need to expound on now. Inside 200 or even 250 yards it is pretty much a draw between the 2 cartridges but if you want to go longer the higher BC wind out with more retained velocity and energy with flatter trajectory.

For the OP, like posted earlier inside 250 yards there really isn't enough difference to matter, past that advantage to the 6.5.

Grendel using published data, same load as above 2289 fps in a 12.5 inch barrel. I used 10 inch barrel since that is what the OP ask about in the first post. In barrels shorter than 16 there is a speed advantage to the 6.8 no doubt but both have enough to be effective. In Barrels 16 and longer. Really it comes down to what someone wants to use. Inside 250 or even 300 yards I doubt there is enough difference to make one much better than the other.

My thinking exactly. 5 years after getting my 6.8 I'm still a happy camper.