6.5 Grendel Barrel Length Comparison

[LRRPF52]

I used worst-case velocities we've been seeing with the newer Hornady 123gr SST lots of ammo.

123gr ELD-M seems to be faster like the old 123gr AMAX load. Supersonic range has the corresponding wind drift with it. 123gr ELD-M isn't the best bullet for long range, but one of the most popular and available, so I used that.

I used .255 doppler-based G7 drag model for the longer range figures with 123gr ELD-M.

I used .462 G1 for the "within 500yds" figures on the 123gr SST for hunting.

All figures are with 100yd zero, 2.5" optic over bore height, standard atmospheric conditions (59° F, 29.53" hg barometric pressure).

Another graph to look at would be weapon weight with pictograph diagrams showing weapon length and profiles.

I need to make a 3D graph showing trajectory and drift, and a weapon size profile graph comparing 6.5 Grendels with other known rifles/cartridges.

[37L1]

Great information. Thanks for posting this.

[Trueblue]

Thanks for posting this. Putting together a 16” build at present. Not seeing much advantage to going to 20-24” after looking at this chart. If I need to reach out past 350 yards, I would use my 6.5 SAUM or 7-300 WM.

[LRRPF52]

Thanks for posting this. Putting together a 16” build at present. Not seeing much advantage to going to 20-24” after looking at this chart. If I need to reach out past 350 yards, I would use my 6.5 SAUM or 7-300 WM.

All those numbers change pretty noticeably for me up at altitude, and I could have used best-case scenario with the highest BC bullets possible, like the 123gr SMK, 123gr Scenar, 130gr Bergers, and 130gr Nosler RDF.

The 18-24" Grendels make a lot of sense for people who want to shoot more LR from 600-1000yds down at sea level in constant wind conditions.

Even with 6.5CM or .260 in shifting winds, getting predictable hits on-target at 1000yds is very hard, even on full-sized silhouettes.

Conditions have and always will determine practical effective range for that time window you shoot in. Higher BC with more speed will extend your effective supersonic reach some, but often that comes back a bit from 1k when wind gets dicey. 6.5 SAUM or 7mm WSM can extend that effective range noticeably for sure.

[Popeye212]

Thanks for posting this

[Ditcher]

I read some where there was data for a 7, 8 and 9" barrel. Anyone know where I can find that?

[Frontier Gear]

Awesome data. Thanks. I'm assuming that this is all based off of the AR15 platform? I ask due to the remark about weapon weight, length and profiles.

It looks like the 16" barrel makes for a a great hunting rifle with SSTs. It is short, non-SBR and good to 350 yards. In my opinion, it is good on coyotes and smaller critters out past it's expansion range as well. Of course an AR15 pistol doesn't need the SBR stamp either.

123gr ELD-M seems to be faster like the old 123gr AMAX load.

I noticed that as well.

[LRRPF52]

I need to photoshop in some performance numbers for each barrel length in this picture, with:

123gr ELD-M mv and supersonic reach
123gr SST mv and expansion range for each

[Big Dog]

That’s great info LRRPF52. Thanks for posting it. To me, it looks like 18”-20” barrels would be the optimal choices. It seems like going to 22” and up doesn’t provide enough advantage to warrant the extra weight. Or ami reading your chart wrong?

[Simple1]

I just built a 12" with faxon barrel. Shooting 123gr ELD reloads with 8208 today, 1.5 MOA just breaking it in. Dont have a chrono to check it yet.

[LRRPF52]

Updated with photo and corresponding numbers for 20”, 18”, 16”, and 12” Grendels with 123gr ELD-M and SST.

[Stugotz]

Good Stuff! Would love the see what you come up with shooting 129gr interlocks.

[LRRPF52]

Good Stuff! Would love the see what you come up with shooting 129gr interlocks.

12” Grendel 129gr Hornady Interlock SP (G1 BC .445), 2182-2294fps

0yds 2200fps mv
225yds 1814fps 942ft-lbs
250yds 1774fps 901ft-lbs

I would use a 35yd zero with that load, puts you 2” high at 100yds assuming a 2.5” high optical plane.

16” Grendel with 129gr SP, 2260fps
250yds 1826fps 955ft-lbs


If you use the 129gr SST instead, the effective expansion threshold range increases to 300yds with the 16” and 250yds with the 12”.

With a 36yd zero in the 12” shooting 129gr SST, you have a no-hold zero out to 200yds, which puts POA 1.9” high at 100yds, -2” at 200yds.

18” Grendel with 129gr SST changes things quite a bit with effective range out to 400yds assuming a 2450fps mv, 50yd zero works best on that for 200yd no-hold setting, which is only .9” high at 100yds.

I’ll have to do one for 129gr ABLR later. That really changes things even more for the better. Gotta get back to filling orders.

[Double Naught Spy]

Very cool. Thank you.

[Stugotz]

12” Grendel 129gr Hornady Interlock SP (G1 BC .445), 2182-2294fps

0yds 2200fps mv
225yds 1814fps 942ft-lbs
250yds 1774fps 901ft-lbs

I would use a 35yd zero with that load, puts you 2” high at 100yds assuming a 2.5” high optical plane.

16” Grendel with 129gr SP, 2260fps
250yds 1826fps 955ft-lbs


If you use the 129gr SST instead, the effective expansion threshold range increases to 300yds with the 16” and 250yds with the 12”.

With a 36yd zero in the 12” shooting 129gr SST, you have a no-hold zero out to 200yds, which puts POA 1.9” high at 100yds, -2” at 200yds.

18” Grendel with 129gr SST changes things quite a bit with effective range out to 400yds assuming a 2450fps mv, 50yd zero works best on that for 200yd no-hold setting, which is only .9” high at 100yds.

I’ll have to do one for 129gr ABLR later. That really changes things even more for the better. Gotta get back to filling orders.

I will be down in Florida in a few weeks hunting hogs at a friends place and shooting this bullet. my barrel is 22" in length and came up with a very accurate load chrono'ed at 2,400fps. Thanks for the info and keep it coming!

[LRRPF52]

22” 6.5 Grendel, 2.5” Optic Plane, 129gr Interlock, .445 G1 BC

I would look at a 50yd zero (.8” high at 100yds) with that set-up for a no-adjustment point blank zero out to ~225yds:

50yds 2306fps 1523ft-lbs 0
75yds 2259fps 1462ft-lbs 0.6” high
100yds 2214fps 1404ft-lbs 0.8” high
125yds 2214fps 1404ft-lbs 0.8” high
150yds 2124fps 1292ft-lbs -0.1” low (2nd zero intersect)
175yds 2079fps 1239ft-lbs -1.3”
200yds 2036fps 1187ft-lbs -2.9”
225yds 1993fps 1137ft-lbs -5.1”
250yds 1950fps 1089ft-lbs -7.9”
275yds 1908fps 1043ft-lbs -11.2”
300yds 1867fps 998ft-lbs -15.1”
325yds 1826fps 955ft-lbs -19.7” (Expansion threshold)

[jackRyan]

We have found that when you drop the boolit weight to say 100-110 grain, The spread increases. There seems to be a 3000 fps limit to this when a 24 inch barrel is used. I was talking with the owner of Sanders Armory, and he was the one that had me experiment with this. Instead of my 18 inch to 24 inch barrel spread in overall speed increasing 90-100 fps on average, the spread became a 210-245 fps increase. Lighter bolts increase at a faster larger rate. The BC change is very minimal in a 6.5 projectile. Has anyone else found this to be the same case. BTW I have never reached 3000 fps and am not one to push the Grendel bolt face after ruining one a while back. I am wanting a 24 inch bolt rifle, so I can push the Grendel outside the AR platform

[VASCAR2]

I have never gotten over 2900 FPS with the 6.5 Grendel with a 85 grain Sierra Varmint or 90 grain TNT bullet. I’m not one to hot rod my reloads but as an example I loaded some 107 grain SMK with 28.5 grains of IMR8208 with CCI 41 primers in Hornady cases. I used a Magnettospeed chronograph and got these velocities out of my 20” Shilen and a Friends Alexander Arms 24” which are both AR-15’s with 1:9 twist. Sierra list 28.5 grains as a max load but Hodgon online data has a higher max charge. I have 24” Cz 527 American and I won’t intentionally load over max charges with it. I have no need to push the envelope with 6.5 Grendel even in a bolt action. With Hornady releasing bolt data for the 6 ARC that might be a better option to get a little more velocity.

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

20" 2658

24" 2729

[myrifle]

We have found that when you drop the boolit weight to say 100-110 grain, The spread increases. There seems to be a 3000 fps limit to this when a 24 inch barrel is used. I was talking with the owner of Sanders Armory, and he was the one that had me experiment with this. Instead of my 18 inch to 24 inch barrel spread in overall speed increasing 90-100 fps on average, the spread became a 210-245 fps increase. Lighter bolts increase at a faster larger rate. The BC change is very minimal in a 6.5 projectile. Has anyone else found this to be the same case. BTW I have never reached 3000 fps and am not one to push the Grendel bolt face after ruining one a while back. I am wanting a 24 inch bolt rifle, so I can push the Grendel outside the AR platform

To the best of my knowledge I am the only bolt grendel owner to ever safely get over the 3000fps mark, actually hitting 3300fps with a 85 grain maker trex from my cz 527 varmint grendel.

I wont give you the load details. Let me say this straight out. Give up and dont chance this idea. It's a waist of time, powder, primers,bullets and you will kill your brass life on the first or second shoot.

Dont chase it, it's not worth it, if you need over 3000fps step up too the short action rounds. The grendel just doesnt have the powder capacity vs brass thickness/strength too push it like that.

[Big_John]

glad I have a 22"



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