Opinions on going from 16” to 18” barrel

[Bruce_Leroy]

Would there be enough benefits on swapping my 16” to an 18”? Gonna use the same barrel I have now, just 18”. Initially the gun was built for hunting but now would like to get into longer range stuff as well, maybe out to 600 yards.

[VASCAR2]

I have two 16” and one 18” 6.5 Grendel AR-15’s and I like all of them. I’ve shot one 16” 6.5 Grendel out to 800 yards and it is fully capable of shooting MOA at 600 yards with factory A-Max if I do my part. Personally if you have a good shooting 6.5 Grendel barrel you’d be better off spending the money on ammo and shooting more. Unfortunately I don’t always follow my own advise and have several 6.5 Grendels.

The difference in velocity is not very much between 16” & 18” in AR-15’s. A Friend and I chronographed these loads a few years ago with a magnetto speed chronograph. We only chronographed five rounds of each but the velocities posted are pretty typical.


123 grain A-Max Hornady

16" 2419

18" 2464

20" 2505

24" 2568

123 Grain SST Hornady

16" 2430

18" 2493

20" 2511

24" 2583

Hand Load 123 Grain Nosler CC, 31.0 grains CFE223, CCI 450

16" 2449

18" 2471

20" 2526

24" 2619

100 Grain FMJ Wolf

16" 2507

18" 2571

20" 2615

24" 2695

[Bruce_Leroy]

Thanks for those results. My 16” is a good shooter. I know that the Grendel can be finicky with accuracy. I’ll just stick with what I have

[rabiddawg]

I know that the Grendel can be finicky with accuracy.

Hmm. Care to explain this notion?

[Bruce_Leroy]

Hmm. Care to explain this notion?

Finicky with accuracy in some barrels is what I meant. I’ve heard of some decent barrel makers in .223 have trouble with their 6.5 Grendel barrels. Sorry about that

[rabiddawg]

Gotcha.

Yeah the round itself isn’t finicky.

[AeroFDE6.5]

Great information- thanks for sharing your data.

Geno

[LRRPF52]

Would there be enough benefits on swapping my 16” to an 18”? Gonna use the same barrel I have now, just 18”. Initially the gun was built for hunting but now would like to get into longer range stuff as well, maybe out to 600 yards.

600yds is pretty boring for just about any barrel length when shooting 6.5 Grendel. At that point, it's just a matter of how much louder you want the impact to be.

Even with my 12" Grendel, 600yds is not much of a challenge unless we drop the plate size below 2 MOA or shoot in higher wind conditions.

I will also say my lightweight Wasp profile Lilja group buy 16" barrel is very accurate. The first 4 groups out of the gate with it were all .69-.84 MOA with 2 different types of ammo, namely PPU 120gr MPT and Hornady 123gr SST.