Looking at either a 20" 6.5 Grendel or a 16" 6.8 SPC II.

Ranges up to 500yds possible but 90% of shots within 200yds. For pigs and deer. Ammo availability not a concern.

I know it's nitpicking but what would you go with?

20" 6.5 Grendel

I went with the 6.5 Grendel.

That means 6.5 Grendel.

come on now 120SST will be fine at 500 I've done it easily now 700 plus it gets tough and the 6.5 might be they best choice. I don't think he can go wrong with either if he doesn't plan to go past 500.

I've spotted both rounds go down range. Throw a cross wind in the equation, and the 6.5 is more repeatable to get hits. The 6.8 was unable to get hits past 700, the 6.5 hit 800 at will, and even hit 1 MOA at 800 multiple times, out of three rifles. No he did not mention past 500, but the data I am sharing should show that the 6.8 is running out of gas at 500 and the 6.5 is not.

I'm not saying anything bad about the 6.8 I know many THFers love it for hunting, and I believe every one of them. I'm just talking about the physics associated with each cartridge.

When you add long range in the mix the grendel is the choice. If it is 100% below 200 yards then 6.8

He really answered his own question by throwing in the 500.

Gotcha and if I wanted to go beyond 500 id go 6.5 as well

He didn't say beyond 500. I'm only saying that AT 500 the 6.5 has the edge.

If you want to go to 500 yards the 6.5 is the right choice. 6.8 is a great guns and I have several but they are not as good a gun at 500 yards as the 6.5 Grendel.

Out of curiosity what are the differences between 6.5 Creedmoor and Grendel? BC, bullet weights, more or less powder? Are their ballistics similar?

So say a fella decided to go 6.5 Grendel, and thought that maybe 600yd would be the maximum; what barrel length would you suggest?

I'm really curious because the 300blk lost its fizz for me. I just sold my upper and supplies and am looking for a better caliber for my lower.

I'm a 6.5 champion, but my 20" Grendel is my go to AR. I don't like 270, but have friends that love their 6.8s for hunting. When I heard about the 6.5 Grendel, I called and talked with Bill Alexander. He told me out to 600 yards the 20" barrel is plenty, but if you want to go for 1000 then get a 24". Then he said "hell if your hunting in East Texas, a 16" is plenty!" I have one of his early .50 Beowulf rifles, he likes the pics of down hogs! Again, I love 6.5s I have several different ones!

6.8 is the mostest optimum answer. Go with it and never look back.

Amount of powder capacity. Creedmoor is basically an improved version of the 260 because Hornady did a real good job on the shoulder geometry. The Grendel was invented in Euro land as they necked down the 7.62x39 to 6.5. Alexander Arms refined the design a little and changed the brass to allow for more PSI. So basically, the 6.5 Creedmoor is a necked down 308 and the 6.5 Grendel is a necked down 7.62x39.

Thanks very informative

That's not informative, that's completely incorrect.

No their ballistics aren't similar, that's why the 6.5 does better at distance. The 6.5 is using a bullet with a better BC, which is why it maintains more velocity down range. When you maintain more velocity down range, you wind drift less, and can retain aerodynamic stability farther out. That's why I lost 6.8 in the air after 700 yards, it went subsonic. But the 6.5 is traveling faster at that distance, therefore it is stable.

Hunting inside of 300 yards, 6.8 with a 16" barrel at the longest.
Pushing past that the 6.5 is better.

Grendel on left, Creedmoor on the right. As you can see, the Creedmoor has a lot more case capacity.

Fireman, looks like u need to spend a little more time slowly reading and a little less time shooting.

From the perspective of a layman, meaning not going into details, they r the same bullet but the creedmoor is a bigger case. So no matter the combination, the creedmoor will have "better ballistics." If it's the same bullet then the cm will shoot faster from muzzle. If u can get the same mv from both calibers, which have no idea if it's possible, then the cm will be a heavier bullet versus the Grendel.

Once again, I'm sure the experts will can tell u of much finer differences but that what it really boils down to.

I think you mis read my question. I was asking about difference between 6.5 Grendel and 6.5 Creedmoor

That's easy to answer. Creedmoor has more powder capacity. Same caliber bullets. Creedmoor also has the ability to fire larger bullets in some guns due to the longer available OAL.

The Grendel will chamber in standard size AR-15 guns. If you want to stay in that same action the Creedmoor requires an AR-10 platform.

Do some research and look at the ballistics for both cartridges.

If you are planning on nothing larger than hogs & deer at ranges under 300 yards I'd shoot the Grendel without hesitation. If you are thinking about having to go past 450 yards or so the Creedmoor gains a huge advantage.

Kind of what I figured thanks

I did misread. My apologies.

Both 6.5 mm bullets, the Creedmoor has more case capacity which will make more velocity. So load a 130 gr AR hybrid in each case, and the Creedmoor pushes the same exact bullet faster.