Requesting opinions regarding 6.5 Grendel for hunting

[hill37]

No problem. Greetings and welcome to the forum. I'm a tight old fart. But mainly I was just trying to get the discussion started.

[Klem]

Fluting a 740 shaves 0.2lb off a 2.43lb barrel. It's not a lot (8%) for an extra $130. If you stick with the unfluted version you can buy the Maxim matching bolt and thread protector instead ($100).

[grayfox]

Yeah I left my 740 as-is, I have a BA that is fluted and truth be told the 740 feels better in hand and during the shot, a little bit but noticeable. So I'd say the fluting idea could be set aside.
Unless you hike over miles of mountainside... my body's not up to miles of hiking any more so I just plan out my walks a bit better and avoid any long stretches. That way my rifle can be what I need it to be.

[crusader18]

There isn’t a lot of difference in velocity with typical 120-125 grain and 129-130 grain hunting bullets in barrels of 18” compared to 20” in 6.5 Grendel. If you use a bullet like the 129 grain Nosler Accu Bond Long Range (ABLR) it expands down to 1300 FPS where many bullets need from 1800 to 2000 FPS to expand depending on projectile. In many cases your looking at approximately 25-50 yards more hunting distance with a 20” barrel compared to a 18” barrel. Elevation and particular hunting bullet with ballistic coefficient and velocity have a bearing on effective range on your particular hunting ammo.

Whether you hunt with a suppressor might dictate a desire for a shorter barrel. Thick wooded terrain or mountainous areas can also dictate which barrel length is more suitable for your area of hunting.

Here are some chronograph results I obtained which will give you an indication of velocities for particular 6.5 Grendel barrel lengths. Lilja, Criterion and Wilson all get very good reviews and can usually be ordered without a delay in shipping. For rack grade barrels Alexander Arms get good reviews as do several other brands. If your interested in accuracy I think it is wise to spend money on a quality barrel.

12” 6.5 Grendel chronograph results


12” PSA SS with LabRadar.


123gr Hornady American Gunner bulk HPBT = 2201 FPS ave with SD of 14.7 (2" to 2.55" groups)
123gr Hornady ELD-M Black = 2265 FPS ave with SD of 13.2 (1.4 to 1.7" groups)
123gr Hornady Custom SST Factory= 2277 ave with SD of 11.8 (2.9 to 3.2" groups)


12” Faxon

Wolf steel case at 2364 Avg. SD was 9.7.

Here is a list of the tested ammo by average velocity for each barrel length. These results were achieved using a Magnetto Speed chronograph in 2016 on a 70-75 degree day. The PPU ammo is older ammo loaded with large rifle primers and has since been recalled by the manufacturer.

120 Grain HP BT PPU

16" 2392

18" 2455

20" 2480

24" 2559

110 grain FMJ PPU

16" 2510

18" 2570

20" 2614

24" 2683

123 grain A-Max Hornady

12” 2265 (123 grain ELD-M)

16" 2419

18" 2464

20" 2505

24" 2568

123 Grain SST Hornady

12” 2277

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

12” 2364

16" 2507

18" 2571

20" 2615

24" 2695

Hand Load 107 Grain SMK 28.5 IMR8208XBR, CCI 41 Hornady cases.

20" 2658

24" 2729

Hornady 123 grain American Gunner

12” 2201

Here is the difference between the 18” barrel compared to the shorter 16” barrel which was slower with every load.

120 grain PPU HP BT

63 FPS difference

110 grain PPU FMJ

60 FPS difference

123 grain A-Max

45 FPS difference

123 grain SST

63 FPS difference

Hand load 123 grain Nosler CC

27 FPS difference

Wolf 100 grain FMJ Steel cased

64 FPS difference


Difference between 20” and 18” barrel 6.5 Grendel

120 grain PPU HP BT

25 FPS difference

110 grain PPU FMJ

44 FPS

123 grain A-Max

41 FPS difference

123 grain SST

18 FPS

Hand load 123 grain Nosler CC

55 FPS difference

Wolf 100 grain FMJ Steel Cased

44 FPS difference

This is all excellent data. I've been looking for a list like this for comparison on barrel lengths, can you tell us what brand barrels you tested on the 18" and 20" and if that should make a substantial difference? I've got a 20" Criterion from PF and an "18 in Criterion coming(also PF). The 20 shoots better than me and I anticipate the the same results from 18". I don't reload so I'm stuck with factory ammo, but that's not so bad either(Hornady 123ssts). I was figuring on 2450 FPS from the 18" and maybe a little less than the advertised .510 BC from Hornady's website. If I were going to use their ballistic calculator, what numbers would get me close with the 123ssts?

[VASCAR2]

The 16” barrel is a 1:9 twist CMV carbine gas system from J&T Distributing. The 18” barrel is Stainless Steel 1:8 twist Grendel II Liberty barrel mid length gas system from Brownell’s. The 20” barrel is a Shilen 1:9 twist Stainless Steel DCM profile rifle length gas system purchased from Midway USA. The 24” barrel is an Alexander Arms CMV 1:9 twist with rifle length gas system.


The results for the 12” PSA and 12” Faxon 6.5 Grendel are from forum members who posted their chronograph results. The shorter 6.5 Grendel in shorter barrel lengths have gotten a lot more common in the last couple of years so I included the data. The results from 16”, 18”, 20” and 24” results were obtained using a MagnetoSpeed and five shot strings.

In my opinion a Hornady 123 grain SST with chronograph around 2475-2500 FPS from an 18” barrel. In cold weather the velocity will probably be closer to 2475 FPS. My results were from a 70-75 degree day so if the temperature is 90+ degrees the velocity will be around 2500 FPS IMHO.

[VASCAR2]

Since conducting the previous chronograph test I assembled a second 16” 6.5 Grendel using a Faxon group buy 1:8 twist mid length gas system barrel. I used a Caldwell chronograph at 10 feet from the muzzle to test the following loads.

Faxon 1:8 6.5 Grendel Chronograph 16" barrel

69* BP 29.79 02-17-17

100 grain Sierra Varmint 29.0 grains H-335 CCI 450 primer

1. 2441
2. 2438
3. 2408
4. 2442
5. 2466

Avg. 2439

STD 20.64

85 grain Sierra Varmint 31.0 grains H-335 CCI 450 primer

1. 2648
2. 2661
3. 2653
4. 2645

Avg. 2651.75

STD 6.99

123 grain Factory Hornady A-MAX

1. 2375
2. 2377
3. 2380
4. 2368
5. 2388

Avg. 2377.6

STD 7.30