6.5 Grendel Velocity..What is realistic?

[KTP1]

Fairly new to the forum here so I apologize if this has been addressed. As I read I see a wide range of velocities reported on the Grendel and Id like to know if what Im seeing is in line. I have learned to love this round in the AR (123 gr Hornady) for shooting hogs but have recently picked up a Howa mini, 20” bolt gun 1:8 twist. Working on loads for the bolt gun with the 100 Nosler and 110 Lehigh Controlled Choas. Both loads are 28 grains of IMR8208XBR with a loaded length of 2.28
Velocity with the Nosler is 2480 and with the Lehigh 2420. Seems slow but maybe not ?
Thanks

[grayfox]

Welcome to the forum.
Several questions need to be answered first...
1. Are you working up loads over a chrony to find what works for your barrel? So these 2 loads, they are results you obtained from your chrony workup?
2. Are you using bullet mfr or powder's mfr or published data, and starting out low and working up? Keep in mind that the published data is also based upon that source's actual barrel length, so may differ from what you have. Many sources are 24" barrels.
3. Elevation above sea level (ASL), temperature and even humidity can affect MV.
MV is affected by barrel length too but you show that as a 20" howa barel. I have shot them and they can be good shooters.

Copper bullets (the lehigh) are harder to seat against the lands so takes relatively more energy to do that, plus it is 10 gr heavier, so a lower MV for the lehigh vs the nosler would not be unexpected.
2480 for a 28.0 gr for a 100 grain cup/core like the Nosler 100, is less than the book max I show for that bullet.
I forgot what I used to use for lehigh's, I haven't shot them for quite a while.

[Harpoon1]

Fairly new to the forum here so I apologize if this has been addressed. As I read I see a wide range of velocities reported on the Grendel and Id like to know if what Im seeing is in line. I have learned to love this round in the AR (123 gr Hornady) for shooting hogs but have recently picked up a Howa mini, 20” bolt gun 1:8 twist. Working on loads for the bolt gun with the 100 Nosler and 110 Lehigh Controlled Choas. Both loads are 28 grains of IMR8208XBR with a loaded length of 2.28
Velocity with the Nosler is 2480 and with the Lehigh 2420. Seems slow but maybe not ?
Thanks

http://www.65grendel.com/forum/showthrea...revolution

http://www.65grendel.com/forum/showthrea...-Gold-Dots

http://www.65grendel.com/forum/showthrea...%E2%80%99s

http://www.65grendel.com/forum/showthrea...%9D-Barrel

http://www.65grendel.com/forum/showthrea...-Gold-Dots

Having said that, I don’t push it anymore, even in the bolt guns. I basically use the Hornady/Speer AR max data (52k psi) and maybe come up .5 grn max in a bolt gun! If that doesn’t group, I’ll try another powder until it does!

31.7- 32.0 grns of H335 under a Speer 90 TNT (good luck finding them right now) is an awesome predator/hog load and should get 2900+ Out of a 20” Howa.

[Koda]

Working on loads for the bolt gun with the 100 Nosler and 110 Lehigh Controlled Choas. Both loads are 28 grains of IMR8208XBR with a loaded length of 2.28
Velocity with the Nosler is 2480 and with the Lehigh 2420. Seems slow but maybe not ?
Thanks

agree that seems slow, seems like you should be able to get faster velocities with a bolt gun. Im getting a tad over 2800fps with a 97gn Absolute Hammer in an AR mag length COAL.
Will your bullet lengths allow you to seat closer to the lands? Try maxing out your seating length for more powder capacity. Dont jam the lands though...

[KTP1]

Welcome to the forum.
Several questions need to be answered first...
1. Are you working up loads over a chrony to find what works for your barrel? So these 2 loads, they are results you obtained from your chrony workup?
2. Are you using bullet mfr or powder's mfr or published data, and starting out low and working up? Keep in mind that the published data is also based upon that source's actual barrel length, so may differ from what you have. Many sources are 24" barrels.
3. Elevation above sea level (ASL), temperature and even humidity can affect MV.
MV is affected by barrel length too but you show that as a 20" howa barel. I have shot them and they can be good shooters.

Copper bullets (the lehigh) are harder to seat against the lands so takes relatively more energy to do that, plus it is 10 gr heavier, so a lower MV for the lehigh vs the nosler would not be unexpected.
2480 for a 28.0 gr for a 100 grain cup/core like the Nosler 100, is less than the book max I show for that bullet.
I forgot what I used to use for lehigh's, I haven't shot them for quite a while.

1. Yes Magnetospeed
2. Yes and also Ive been reloading for several years so yep reviewed several data sources. A couple of the data sources were using 24” barrels, so my 20” could be as much as 100 fps under that published data.
3. 1100 ft, 35 degrees 48% RH. Id also need to double check how far I’m off the lands. I measured the chamber but not near my data book.
Both bullets were very accurate.
Just wanted a gut check on the velocity.
Thanks a bunch.

[KTP1]

http://www.65grendel.com/forum/showthrea...revolution

http://www.65grendel.com/forum/showthrea...-Gold-Dots

http://www.65grendel.com/forum/showthrea...%E2%80%99s

http://www.65grendel.com/forum/showthrea...%9D-Barrel

http://www.65grendel.com/forum/showthrea...-Gold-Dots

Having said that, I don’t push it anymore, even in the bolt guns. I basically use the Hornady/Speer AR max data (52k psi) and maybe come up .5 grn max in a bolt gun! If that doesn’t group, I’ll try another powder until it does!

31.7- 32.0 grns of H335 under a Speer 90 TNT (good luck finding them right now) is an awesome predator/hog load and should get 2900+ Out of a 20” Howa.

Thank you Harpoon. Appreciate the links

[KTP1]

BFT’s lengthy load list is also really good!

[grayfox]

I think for the 100 Nosler's, I topped out at around 29-29.8 gr. This charge may vary based on what brass you use, they all differ as to internal useable volume. 2650-2700 for a 20" barrel.
And when I was trying the 110 chaos, believe I was getting 2575 with XBR out of an 18" barrel, but that was a max speed as I recall, definitely a warm load. Which is why we always say to start out low and work up... A bolt action like howa might get to 2600 +/- but it will be close or over 52000 saami (primarily set for gas guns).

You're of course looking for a good node and consistent accuracy, not just the max speed.

[LRRPF52]

As to barrel lengths, if we look at 1 bullet (123gr SST) and compare from 10.5” to 24”:

10.5” 2200-2250fps 260-270yds expansion, 225yds PBZ, 875yds supersonic
12.5” 2280-2350fps 300-350yds expansion, 240yds PBZ, 900yds supersonic

14.5” 2350-2420fps 350-400yds expansion, 240yds PBZ, 950yds supersonic
16” --2420-2470fps 400-420yds expansion, 250yds PBZ, 975yds supersonic
18” --2450-2500fps 410-440yds expansion, 250yds PBZ, 1000yds supersonic

20” --2520-2590fps 450-490yds expansion, 250yds PBZ, 1050yds supersonic
22” --2550-2620fps 475-525yds expansion, 255yds PBZ, 1075yds supersonic
24” --2590-2640fps 500-520yds expansion, 260yds PBZ, 1100yds supersonic

[Harpoon1]

As to barrel lengths, if we look at 1 bullet (123gr SST) and compare from 10.5” to 24”:

10.5” 2200-2250fps 260-270yds expansion, 225yds PBZ, 875yds supersonic
12.5” 2280-2350fps 300-350yds expansion, 240yds PBZ, 900yds supersonic

14.5” 2350-2420fps 350-400yds expansion, 240yds PBZ, 950yds supersonic
16” --2420-2470fps 400-420yds expansion, 250yds PBZ, 975yds supersonic
18” --2450-2500fps 410-440yds expansion, 250yds PBZ, 1000yds supersonic

20” --2520-2590fps 450-490yds expansion, 250yds PBZ, 1050yds supersonic
22” --2550-2620fps 475-525yds expansion, 255yds PBZ, 1075yds supersonic
24” --2590-2640fps 500-520yds expansion, 260yds PBZ, 1100yds supersonic

I see you’re in Utah, are those Supersonic numbers for your local “avg” density altitude? Or adjusted for a standard day @ sea level?

[KTP1]

I think for the 100 Nosler's, I topped out at around 29-29.8 gr. This charge may vary based on what brass you use, they all differ as to internal useable volume. 2650-2700 for a 20" barrel.
And when I was trying the 110 chaos, believe I was getting 2575 with XBR out of an 18" barrel, but that was a max speed as I recall, definitely a warm load. Which is why we always say to start out low and work up... A bolt action like howa might get to 2600 +/- but it will be close or over 52000 saami (primarily set for gas guns).

You're of course looking for a good node and consistent accuracy, not just the max speed.

Grayfox you’re spot on with that last statement. Both of my loads have been very accurate at current velocities so I also appreciate your numbers. I will continue tweaking and thats why we do what we do.

LRRPF52, I think I need to do a better job measuring velocity. Maybe if I show the better half this thread she’ll be all in for a new Garmin!!!

[Harpoon1]

As to barrel lengths, if we look at 1 bullet (123gr SST) and compare from 10.5” to 24”:

10.5” 2200-2250fps 260-270yds expansion, 225yds PBZ, 875yds supersonic
12.5” 2280-2350fps 300-350yds expansion, 240yds PBZ, 900yds supersonic

14.5” 2350-2420fps 350-400yds expansion, 240yds PBZ, 950yds supersonic
16” --2420-2470fps 400-420yds expansion, 250yds PBZ, 975yds supersonic
18” --2450-2500fps 410-440yds expansion, 250yds PBZ, 1000yds supersonic

20” --2520-2590fps 450-490yds expansion, 250yds PBZ, 1050yds supersonic
22” --2550-2620fps 475-525yds expansion, 255yds PBZ, 1075yds supersonic
24” --2590-2640fps 500-520yds expansion, 260yds PBZ, 1100yds supersonic

I see you’re in Utah. Are those supersonic speeds for your local density altitude or are they adjusted for a standard day @ sea level?

[LRRPF52]

I see you’re in Utah. Are those supersonic speeds for your local density altitude or are they adjusted for a standard day @ sea level?

Those are all sea level, standard atmosphere. Muzzle Velocity will be the same regardless of DA, but downrange performance will be better in the thin air, higher temps.

Up where I like to shoot, an 18” Grendel out-performs a 24” Grendel at sea level.

Lowest places I can find are 4400ft above sea level. My favorite range is 6300ft.

[Harpoon1]

Those are all sea level, standard atmosphere. Muzzle Velocity will be the same regardless of DA, but downrange performance will be better in the thin air, higher temps.

Muzzle velocity doesn’t change with DA but the speed of sound (transonic zone) does! That’s why I asked!

[biodsl]

'52s 22" velocities are similar to mine out of a 22" Black Hole Weaponry barrel. Using 31.2grs of CFE 223, I get between 2500 and 2640 depending on ambient temperatures.

[LRRPF52]

Muzzle velocity doesn’t change with DA but the speed of sound (transonic zone) does! That’s why I asked!

Yup. Tracking all that from aerospace experience.

We always had to check DA when planning flights since AFFTC and some of the airfields we flew out of frequently were well above sea level and hot in the summer, pretty cold in the winter, and close to the CA coast to where weather changes from the Sierra Nevadas were frequent.

It’s also a huge factor in weapons test, namely missiles. DA is totally different up in the higher altitude bands, and if a target is in the lower bands, it affects performance (range and terminal envelope) tremendously.

Same in the Army with planning for rotary wing operations or Air Load Planning, though the Load Masters and pilots work that out for the heavies. I went to the school for it though where we had to do the manual work, even though the Loadmasters have a computer for it where they enter in all the load weights to provide total cargo to the pilots/co-pilots/flight engineers.

For rotary wing, it affects what birds can go where, especially in places with higher elevations and high temps. Chinook (CH-47 and MH-47) was king in that space due to how much power it has with dual turboshafts. MH-53J AFSOC birds had a lot of power too.
UH-60s and AH-64s are limited in what loads they can carry and where they can go relative to higher altitudes and temps.

Cold air is almost always better for flying though when looking at lift and power-to-weight, which is why US fighters set their time-to-climb records up in North Dakota. Russians needed to find “warmer" places since they’re at Hudson Bay latitude. Their warm is not fun for a lot of us. I frequently tell people who I see shivering here in Utah, “Hey, this is a beautiful spring day in Finland."

Hot air gets really tricky for flying, especially at higher elevations. A lot of your single engine general aviation mishaps occur due to overweight, underpowered, and thin hot air.

But it’s great for bullets and retaining energy downrange. Layman answer to all of this is use faster twist rate if you’re worried about transonic range. This map is great for basic reference for where the higher elevations are in the US:

[LRRPF52]

'52s 22" velocities are similar to mine out of a 22" Black Hole Weaponry barrel. Using 31.2grs of CFE 223, I get between 2500 and 2640 depending on ambient temperatures.

Those mv figures I listed cover a wide range of samples observed by many Grendel shooters over the years, as well as factory ammo box velocities.

They are not limited to my personal observed and recorded chronograph readings, though those fit within the listed ranges except for one data set.

There was one hot day where I recorded the following from my first 16” AA Grendel barrel, shooting moly-coated 123gr Scenars PF factory load:

2522
2484
2582
2518
2503

2522fps avg 15ft from the muzzle. That was unusually-fast for a 16” Grendel with 123gr Scenar. I shot the crap out of that barrel/bolt combo too, never had an issue with it.

I shot the same load later and got:

2447
2451
2454
2450

.792” group at 100yds as well

[Harpoon1]

Hot air gets really tricky for flying, especially at higher elevations. A lot of your single engine general aviation mishaps occur due to overweight, underpowered, and thin hot air.

Yep I’m familiar! Im in my C182 bumping around the Idaho/Montana backcountry a few summers ago!

https://www.youtube.com/@58harwood/videos

[Timitus]

Yep I’m familiar! Im in my C182 bumping around the Idaho/Montana backcountry a few summers ago!

https://www.youtube.com/@58harwood/videos

Nice way to see some beautiful country.

[LRRPF52]

Yep I’m familiar! Im in my C182 bumping around the Idaho/Montana backcountry a few summers ago!

https://www.youtube.com/@58harwood/videos

One of those had my butt puckering as you were landing in that higher altitude canyon.

Our family doctor died in a crash in the Tehachapi Mountains doing less-dangerous flying in the early 1980s.