Powder Temp Stability Test – 8028XBR, Varget, H4350, RL19, RL26, N560

[Carbine Kid]

Powder Temp Stability Test – 8028XBR, Varget, H4350, RL19, RL26, N560
G'day jamiebolseth.
American Varget is made by Australian Defence Industries (ADI) and is one of the Australian Rifle Series.
Your experience is what I would expect. Varget = AR 2208. Now AR2208 and AR2206H in a 308 are only 3 to 4gn apart with 2206h being slightly faster. In 55 years of reloading I have done extensive testing of all the AR series.
Temperatures where I live vary from 31 to 104F. I have had 2206h go up by up to 28fps with a 60* drop in temperature and similar with 2208.
Your testing is accurate, well done. I love days when the only thing you can do experiment with loading.

Really cold weather, plus boredom inspired me to conduct a fairly extensive powder stability test this weekend on several of my hunting rifles.


Rifle Specs…

300 WSM – 1:10 twist 20" Proof Carbon barrel
7 SAUM – 1:9 twist 26" Proof Carbon barrel
308 Win – 1:11.25 twist 20" Bartlein barrel
6.5 Creedmoor – 1:8 twist 22" Bartlein barrel
6.5x47 Lapua – 1:8 twist 26" Bartlein barrel (target rifle)
223 Rem – 1:8 twist 24" Bartlein barrel (target rifle)

Testing Procedure…
4-6 shots (usually 5) were shot with cold ammo/rifle, then 4-6 shots were shot with Warm ammo/rifle. Speeds were recorded with a Labradar, and I did not delete ANY of the shots, so any outliers were left in the data. Cold ammo was left out overnight with Temps around -5 to +5 degrees F. Actual temp was recorded at the time of shooting the Cold Group. For Cold group shooting the rifle was left outside for at least an hour for the bore to get cold. Warm Groups were shot with ammo that was left in my house at 70 degrees F, and the Rifle was stored in my work shop for at least 1 hour prior to shooting, which is kept at 55 degrees F. Then the ammo was quickly loaded and shot outside within 5 min.


I will summarize the data below by including the following…

*******************************
Powder Type
Caliber
Load Data

Warm Group Temp
Warm Group Avg
Warm Group SD

Cold Group Temp
Cold Group Avg
Cold Group SD

Temp Difference
Avg Vel Difference



*********Here's the Data***********
THE USUAL DISCLAMERS APPLY WITH THE LOAD DATA.
!!WORK UP YOUR OWN LOADS FOR YOUR RIFLES!!
*****************************************************

Powder Type – H4350
Caliber – 6.5x47 Lapua
Load Data – 40.0gns, Lapua Case, CCI450, 140 Hybrid

Warm Group Temp = 70F
Warm Group Avg - 2781 fps
Warm Group SD – 1.8 fps

Cold Group Temp = 10F
Cold Group Avg - 2767
Cold Group SD – 10.5

Temp Difference – 60 Degrees
Avg Vel Difference – 15 fps


NOTE: Good SD's and Temp stability with H4350 and the 6.5x47. Most info I've read says about 0.3 FPS per degree of temp change, and that's about what I saw. No surprise here.



*****************************************************

Powder Type – H4350
Caliber – 6.5 Creedmoor
Load Data – 42.2gns, Lapua SRP Case, CCI450, 143 ELDX

Warm Group Temp = 70F
Warm Group Avg - 2676 fps
Warm Group SD – 23.1 fps

Cold Group Temp = 10F
Cold Group Avg - 2649
Cold Group SD – 11.5

Temp Difference – 60 Degrees
Avg Vel Difference – 27 fps


NOTES: The high SD on the Warm Group was mainly due to the very first shot, which was about 50 fps slower than the rest (not sure why). Also note that if you've ever heard of Small Rifle Primers being unreliable with large cases in cold weather, well… I had two rounds misfire on the Cold Group. One of them I tried again and it fired. The other never fired after 3 tries. The 27 fps difference over a 60 degree change is about 0.5 fps per degree. This seems a little high for H4350, but not out of the ordinary.


*****************************************************

Powder Type – H4350
Caliber – 300WSM
Load Data – 63.0gns, Norma Case, CCI250, 178 ELDX

Warm Group Temp = 70F
Warm Group Avg - 2916 fps
Warm Group SD – 18.6 fps

Cold Group Temp = 2F
Cold Group Avg - 2912
Cold Group SD – 9.2

Temp Difference – 68 Degrees
Avg Vel Difference – 4 fps

NOTE: I haven't finished load development with this rifle, but liked what I saw from the results above, so I reran the same test with a slightly lower charge weight. Results below.

*****************************************************

Powder Type – H4350
Caliber – 300WSM
Load Data – 62.5gns, Norma Case, CCI250, 178 ELDX

Warm Group Temp = 55F
Warm Group Avg - 2926 fps
Warm Group SD – 10.0 fps

Cold Group Temp = -5F
Cold Group Avg - 2912
Cold Group SD – 13.6

Temp Difference – 60 Degrees
Avg Vel Difference – 14 fps

NOTE: Still outstanding temp stability in the 300 WSM. I will be working in this range more to develop my hunting load for this rifle.


*****************************************************

Powder Type – RL26
Caliber – 7SAUM
Load Data – 59.2gns, Norma Case, CCI250, 180 VLD

Warm Group Temp = 70F
Warm Group Avg - 2870 fps
Warm Group SD – 5.6 fps

Cold Group Temp = 2F
Cold Group Avg – 2846 fps
Cold Group SD – 8.3

Temp Difference – 68 Degrees
Avg Vel Difference – 24 fps


NOTE: This rifle and load are very well proven for me (low SD's always consistent), so I have a lot of confidence in these numbers. RL26 looks to be about 0.35 fps per degree of temp change. Not bad at all for a powder that is not technically "Temperature Stable".


*****************************************************

Powder Type – 8028XBR
Caliber – 223 Rem
Load Data – 22.5gns, Hornady Case, CCI200, 69 TMK

Warm Group Temp = 70F
Warm Group Avg - 2729 fps
Warm Group SD – 23.8 fps

Cold Group Temp = 10F
Cold Group Avg – 2683 fps
Cold Group SD – 12.1 fps

Temp Difference – 60 Degrees
Avg Vel Difference – 46 fps


NOTE: This rifle and load are just for practicing out to 300 yds, so I don't take a lot of care in loading the ammo, which gives me higher SD's. However, it's apparent that the 8028XBR is effected by low temps quite a bit.


*****************************************************

Powder Type – RL19
Caliber – 300 WSM
Load Data – 66.0gns, Norma Case, CCI250, 200 ELDX

Warm Group Temp = 70F
Warm Group Avg - 2862 fps
Warm Group SD – 30.1 fps

Cold Group Temp = 10F
Cold Group Avg – 2823 fps
Cold Group SD – 24.9 fps

Temp Difference – 60 Degrees
Avg Vel Difference – 39 fps


NOTE: This load just doesn't shoot very well in my rifle, but I had a few rounds laying around from an early attempt at load development, so decide to shoot them. With such high SD's I wouldn't trust this data much, but it shows RL19 to be fairly temp sensitive, which is consistent with what most people say about it.



*****************************************************

Powder Type – N560
Caliber – 300 WSM
Load Data – Norma Case, CCI250, 178 ELDX

Warm Group Temp = 70F
Warm Group Avg - 2932 fps
Warm Group SD – 13.9 fps

Cold Group Temp = 4F
Cold Group Avg – 2847 fps
Cold Group SD – 14.9 fps

Temp Difference – 66 Degrees
Avg Vel Difference – 85 fps!!

NOTE: This was the big loser of this test. I lost 85 fps over a 66 degree temp change! I'm not loading any more of this N560.


*****************************************************

And now for the weirdest of the results…. VARGET, which actually sped up as it got colder…

*****************************************************

Powder Type – Varget
Caliber – 308 Win
Load Data – 45.0gns, Fed Case, CCI200, 165 Partition

Warm Group Temp = 70F
Warm Group Avg - 2699 fps
Warm Group SD – 12.9 fps

Cold Group Temp = 10F
Cold Group Avg – 2724 fps
Cold Group SD – 11.5 fps

Temp Difference – 60 Degrees
Avg Vel Difference – This load was 25 FPS FASTER with a 60 degree Drop in temp.


NOTE: I figured this test could not be right, so I ran it again the next day. Here's that data…


*****************************************************

Powder Type – Varget
Caliber – 308 Win
Load Data – 45.0gns, Fed Case, CCI200, 165 Partition

Warm Group Temp = 70F
Warm Group Avg - 2696 fps
Warm Group SD – 8.7 fps

Cold Group Temp = 2F
Cold Group Avg – 2716 fps
Cold Group SD – 13.5 fps

Temp Difference – 68 Degrees
Avg Vel Difference – This load was 20 FPS FASTER with a 68 degree Drop in temp???

NOTE: I don't understand the Varget results. Weird thing is I haven't shot this rifle/ammo for about a year. I had a bunch of round loaded for it that I remember developing in the summer time (so probably 80-90 degrees), and the boxes were labeled as having a velocity of 2660 fps. So I was surprised to see velocities around 2700 fps when I shot the warm group. Then even more surprised with I saw them speed up with single digits temps.


****************
Summary
****************

I mostly found that H4350 is fairly temp stable in the 0.2-0.4 fps per degree range. I also was pleased to find that RL26 was fairly temp stable. N560 was awful, as was 8028XBR (but I only use this for 223 practice ammo).

With regard to Varget getting faster as it gets colder, I am stumped by this. Maybe it has something to do with my specific barrel, or bullet combo. Not sure.

Hope the data is helpful to people.

Powder Temp Stability Test – 8028XBR, Varget, H4350, RL19, RL26, N560


Really cold weather, plus boredom inspired me to conduct a fairly extensive powder stability test this weekend on several of my hunting rifles.


Rifle Specs…

300 WSM – 1:10 twist 20" Proof Carbon barrel
7 SAUM – 1:9 twist 26" Proof Carbon barrel
308 Win – 1:11.25 twist 20" Bartlein barrel
6.5 Creedmoor – 1:8 twist 22" Bartlein barrel
6.5x47 Lapua – 1:8 twist 26" Bartlein barrel (target rifle)
223 Rem – 1:8 twist 24" Bartlein barrel (target rifle)

Testing Procedure…
4-6 shots (usually 5) were shot with cold ammo/rifle, then 4-6 shots were shot with Warm ammo/rifle. Speeds were recorded with a Labradar, and I did not delete ANY of the shots, so any outliers were left in the data. Cold ammo was left out overnight with Temps around -5 to +5 degrees F. Actual temp was recorded at the time of shooting the Cold Group. For Cold group shooting the rifle was left outside for at least an hour for the bore to get cold. Warm Groups were shot with ammo that was left in my house at 70 degrees F, and the Rifle was stored in my work shop for at least 1 hour prior to shooting, which is kept at 55 degrees F. Then the ammo was quickly loaded and shot outside within 5 min.


I will summarize the data below by including the following…

*******************************
Powder Type
Caliber
Load Data

Warm Group Temp
Warm Group Avg
Warm Group SD

Cold Group Temp
Cold Group Avg
Cold Group SD

Temp Difference
Avg Vel Difference



*********Here's the Data***********
THE USUAL DISCLAMERS APPLY WITH THE LOAD DATA.
!!WORK UP YOUR OWN LOADS FOR YOUR RIFLES!!
*****************************************************

Powder Type – H4350
Caliber – 6.5x47 Lapua
Load Data – 40.0gns, Lapua Case, CCI450, 140 Hybrid

Warm Group Temp = 70F
Warm Group Avg - 2781 fps
Warm Group SD – 1.8 fps

Cold Group Temp = 10F
Cold Group Avg - 2767
Cold Group SD – 10.5

Temp Difference – 60 Degrees
Avg Vel Difference – 15 fps


NOTE: Good SD's and Temp stability with H4350 and the 6.5x47. Most info I've read says about 0.3 FPS per degree of temp change, and that's about what I saw. No surprise here.



*****************************************************

Powder Type – H4350
Caliber – 6.5 Creedmoor
Load Data – 42.2gns, Lapua SRP Case, CCI450, 143 ELDX

Warm Group Temp = 70F
Warm Group Avg - 2676 fps
Warm Group SD – 23.1 fps

Cold Group Temp = 10F
Cold Group Avg - 2649
Cold Group SD – 11.5

Temp Difference – 60 Degrees
Avg Vel Difference – 27 fps


NOTES: The high SD on the Warm Group was mainly due to the very first shot, which was about 50 fps slower than the rest (not sure why). Also note that if you've ever heard of Small Rifle Primers being unreliable with large cases in cold weather, well… I had two rounds misfire on the Cold Group. One of them I tried again and it fired. The other never fired after 3 tries. The 27 fps difference over a 60 degree change is about 0.5 fps per degree. This seems a little high for H4350, but not out of the ordinary.


*****************************************************

Powder Type – H4350
Caliber – 300WSM
Load Data – 63.0gns, Norma Case, CCI250, 178 ELDX

Warm Group Temp = 70F
Warm Group Avg - 2916 fps
Warm Group SD – 18.6 fps

Cold Group Temp = 2F
Cold Group Avg - 2912
Cold Group SD – 9.2

Temp Difference – 68 Degrees
Avg Vel Difference – 4 fps

NOTE: I haven't finished load development with this rifle, but liked what I saw from the results above, so I reran the same test with a slightly lower charge weight. Results below.

*****************************************************

Powder Type – H4350
Caliber – 300WSM
Load Data – 62.5gns, Norma Case, CCI250, 178 ELDX

Warm Group Temp = 55F
Warm Group Avg - 2926 fps
Warm Group SD – 10.0 fps

Cold Group Temp = -5F
Cold Group Avg - 2912
Cold Group SD – 13.6

Temp Difference – 60 Degrees
Avg Vel Difference – 14 fps

NOTE: Still outstanding temp stability in the 300 WSM. I will be working in this range more to develop my hunting load for this rifle.


*****************************************************

Powder Type – RL26
Caliber – 7SAUM
Load Data – 59.2gns, Norma Case, CCI250, 180 VLD

Warm Group Temp = 70F
Warm Group Avg - 2870 fps
Warm Group SD – 5.6 fps

Cold Group Temp = 2F
Cold Group Avg – 2846 fps
Cold Group SD – 8.3

Temp Difference – 68 Degrees
Avg Vel Difference – 24 fps


NOTE: This rifle and load are very well proven for me (low SD's always consistent), so I have a lot of confidence in these numbers. RL26 looks to be about 0.35 fps per degree of temp change. Not bad at all for a powder that is not technically "Temperature Stable".


*****************************************************

Powder Type – 8028XBR
Caliber – 223 Rem
Load Data – 22.5gns, Hornady Case, CCI200, 69 TMK

Warm Group Temp = 70F
Warm Group Avg - 2729 fps
Warm Group SD – 23.8 fps

Cold Group Temp = 10F
Cold Group Avg – 2683 fps
Cold Group SD – 12.1 fps

Temp Difference – 60 Degrees
Avg Vel Difference – 46 fps


NOTE: This rifle and load are just for practicing out to 300 yds, so I don't take a lot of care in loading the ammo, which gives me higher SD's. However, it's apparent that the 8028XBR is effected by low temps quite a bit.


*****************************************************

Powder Type – RL19
Caliber – 300 WSM
Load Data – 66.0gns, Norma Case, CCI250, 200 ELDX

Warm Group Temp = 70F
Warm Group Avg - 2862 fps
Warm Group SD – 30.1 fps

Cold Group Temp = 10F
Cold Group Avg – 2823 fps
Cold Group SD – 24.9 fps

Temp Difference – 60 Degrees
Avg Vel Difference – 39 fps


NOTE: This load just doesn't shoot very well in my rifle, but I had a few rounds laying around from an early attempt at load development, so decide to shoot them. With such high SD's I wouldn't trust this data much, but it shows RL19 to be fairly temp sensitive, which is consistent with what most people say about it.



*****************************************************

Powder Type – N560
Caliber – 300 WSM
Load Data – Norma Case, CCI250, 178 ELDX

Warm Group Temp = 70F
Warm Group Avg - 2932 fps
Warm Group SD – 13.9 fps

Cold Group Temp = 4F
Cold Group Avg – 2847 fps
Cold Group SD – 14.9 fps

Temp Difference – 66 Degrees
Avg Vel Difference – 85 fps!!

NOTE: This was the big loser of this test. I lost 85 fps over a 66 degree temp change! I'm not loading any more of this N560.


*****************************************************

And now for the weirdest of the results…. VARGET, which actually sped up as it got colder…

*****************************************************

Powder Type – Varget
Caliber – 308 Win
Load Data – 45.0gns, Fed Case, CCI200, 165 Partition

Warm Group Temp = 70F
Warm Group Avg - 2699 fps
Warm Group SD – 12.9 fps

Cold Group Temp = 10F
Cold Group Avg – 2724 fps
Cold Group SD – 11.5 fps

Temp Difference – 60 Degrees
Avg Vel Difference – This load was 25 FPS FASTER with a 60 degree Drop in temp.


NOTE: I figured this test could not be right, so I ran it again the next day. Here's that data…


*****************************************************

Powder Type – Varget
Caliber – 308 Win
Load Data – 45.0gns, Fed Case, CCI200, 165 Partition

Warm Group Temp = 70F
Warm Group Avg - 2696 fps
Warm Group SD – 8.7 fps

Cold Group Temp = 2F
Cold Group Avg – 2716 fps
Cold Group SD – 13.5 fps

Temp Difference – 68 Degrees
Avg Vel Difference – This load was 20 FPS FASTER with a 68 degree Drop in temp???

NOTE: I don't understand the Varget results. Weird thing is I haven't shot this rifle/ammo for about a year. I had a bunch of round loaded for it that I remember developing in the summer time (so probably 80-90 degrees), and the boxes were labeled as having a velocity of 2660 fps. So I was surprised to see velocities around 2700 fps when I shot the warm group. Then even more surprised with I saw them speed up with single digits temps.


****************
Summary
****************

I mostly found that H4350 is fairly temp stable in the 0.2-0.4 fps per degree range. I also was pleased to find that RL26 was fairly temp stable. N560 was awful, as was 8028XBR (but I only use this for 223 practice ammo).

With regard to Varget getting faster as it gets colder, I am stumped by this. Maybe it has something to do with my specific barrel, or bullet combo. Not sure.

Hope the data is helpful to people.

 

[CUTTER1]

I did a bunch of teasing this last fall and early winter. N550 is undoubtably the most unstable powder I've ever tested. It is sensative with pressure at high and low temperatures! RL26 and RL33 as well as H4350 have been very stable in my testing
Doc

 

[10ring1]

Great write up. Thank you. My Varget warm groups were tight but in freezing temps, they sucked.

 

[hunter284]

I did a bunch of teasing this last fall and early winter. N550 is undoubtably the most unstable powder I've ever tested. It is sensative with pressure at high and low temperatures! RL26 and RL33 as well as H4350 have been very stable in my testing
Doc

Thanks for the info. It's great to know this type of info when deciding which powders to begin load development according to the type of weather I will be hunting in.

 

[slv hunter]

Thanks for sharing the info and the time and effort you put into getting it.

 

[bbraden]

Great work and thanks for sharing! I wonder if the metal properties of our barrels could have anything to do with it shooting slower in the cold. i.e., cold barrel contracts causing a miniscully smaller bore diameter which leads to more constriction on the bullet and hence slower muzzle velocities?

 

[Pdvdh]

Great work and thanks for sharing! I wonder if the metal properties of our barrels could have anything to do with it shooting slower in the cold. i.e., cold barrel contracts causing a miniscully smaller bore diameter which leads to more constriction on the bullet and hence slower muzzle velocities?

Some folks test powder temp sensitivity by only cooling down their ammo, with their rifles remaining at higher temperature. They also report lower MV with solely cold ammo, by and large.

Also, the bullets would be a little smaller in diameter at the colder temps also. Not just the barrel.

Just some thoughts to ponder...

When I test, both ammo and rifle are brought to the same ambient temperature. Which means I don't let the barrel get hot during testing. One shot, and the gun is left alone until it comes back down to temp. Which is just one more reason why my testing is so time consuming.

 

[orange1948]

Thanks for all your work. Great report.
Duane

 

[bbraden]

Some folks test powder temp sensitivity by only cooling down their ammo, with their rifles remaining at higher temperature. They also report lower MV with solely cold ammo, by and large.

Also, the bullets would be a little smaller in diameter at the colder temps also. Not just the barrel.

Just some thoughts to ponder...

When I test, both ammo and rifle are brought to the same ambient temperature. Which means I don't let the barrel get hot during testing. One shot, and the gun is left alone until it comes back down to temp. Which is just one more reason why my testing is so time consuming.

I agree 100% that colder powder is probably the bulk of the change in velocities; just proposing an alternative theory that might account for a small bit of the difference. As for the bullet also being smaller, I thought about that but recognize that we're talking about three different metals and hence expansion/contraction rates - steel (barrel), copper (jacket), lead (core).

 

[Pdvdh]

When the barrel is left warm, and the ammo and bullet are chilled, the steel bore remains warm temperature ID, while the bullet OD is reduced.
If bore and bullet diameters play a significant role, I think it would be much more pronounced by elevating the bore temperature thru repetitive shots fired. I do think I see this affect after chronographing a thousand and more bullet velocities over the years.

Which is why my temp sensitivity testing involves one shot at all temps tested. Then allow bore to return to ammo temperature before collecting another MV.

 

[tankgijohn72]

Velocity readings over various temperatures with different powder/cartridge combinations dont always give you a consistent 0.5fps per degree. I worked for awhile in a ballistic lab, and you have illuminated what is a common misconception. Higher temp does not always mean higher velocity. In my own testing at home I have seen a couple cases where velocity got higher at lower temp with my .270. It is hard to perform at home without a temperature conditioning chamber. But if you had one and could plot MV results from say -20 to 120 degrees in 10 degree increments you can accurately characterize a powder/cartridge/bullet combo. Results are not always linear. Data doesn't lie.

*******

And now for the weirdest of the results…. VARGET, which actually sped up as it got colder…

*****************************************************

Powder Type – Varget
Caliber – 308 Win
Load Data – 45.0gns, Fed Case, CCI200, 165 Partition

Warm Group Temp = 70F
Warm Group Avg - 2699 fps
Warm Group SD – 12.9 fps

Cold Group Temp = 10F
Cold Group Avg – 2724 fps
Cold Group SD – 11.5 fps

Temp Difference – 60 Degrees
Avg Vel Difference – This load was 25 FPS FASTER with a 60 degree Drop in temp.


NOTE: I figured this test could not be right, so I ran it again the next day. Here's that data…


*****************************************************

Powder Type – Varget
Caliber – 308 Win
Load Data – 45.0gns, Fed Case, CCI200, 165 Partition

Warm Group Temp = 70F
Warm Group Avg - 2696 fps
Warm Group SD – 8.7 fps

Cold Group Temp = 2F
Cold Group Avg – 2716 fps
Cold Group SD – 13.5 fps

Temp Difference – 68 Degrees
Avg Vel Difference – This load was 20 FPS FASTER with a 68 degree Drop in temp???

NOTE: I don't understand the Varget results. Weird thing is I haven't shot this rifle/ammo for about a year. I had a bunch of round loaded for it that I remember developing in the summer time (so probably 80-90 degrees), and the boxes were labeled as having a velocity of 2660 fps. So I was surprised to see velocities around 2700 fps when I shot the warm group. Then even more surprised with I saw them speed up with single digits temps.


****************
Summary
****************

I mostly found that H4350 is fairly temp stable in the 0.2-0.4 fps per degree range. I also was pleased to find that RL26 was fairly temp stable. N560 was awful, as was 8028XBR (but I only use this for 223 practice ammo).

With regard to Varget getting faster as it gets colder, I am stumped by this. Maybe it has something to do with my specific barrel, or bullet combo. Not sure.

Hope the data is helpful to people.[/QUOTE]

 

[Gills]

I've been trying to decide on iMessage 4350 or viht n160. For my 7 mag if n160 is like the n560. I'll use the 4350 despite the slightly larger groups

 

[Saracen]

Powder Temp Stability Test – 8028XBR, Varget, H4350, RL19, RL26, N560


Really cold weather, plus boredom inspired me to conduct a fairly extensive powder stability test this weekend on several of my hunting rifles.


Rifle Specs…

300 WSM – 1:10 twist 20" Proof Carbon barrel
7 SAUM – 1:9 twist 26" Proof Carbon barrel
308 Win – 1:11.25 twist 20" Bartlein barrel
6.5 Creedmoor – 1:8 twist 22" Bartlein barrel
6.5x47 Lapua – 1:8 twist 26" Bartlein barrel (target rifle)
223 Rem – 1:8 twist 24" Bartlein barrel (target rifle)

Testing Procedure…
4-6 shots (usually 5) were shot with cold ammo/rifle, then 4-6 shots were shot with Warm ammo/rifle. Speeds were recorded with a Labradar, and I did not delete ANY of the shots, so any outliers were left in the data. Cold ammo was left out overnight with Temps around -5 to +5 degrees F. Actual temp was recorded at the time of shooting the Cold Group. For Cold group shooting the rifle was left outside for at least an hour for the bore to get cold. Warm Groups were shot with ammo that was left in my house at 70 degrees F, and the Rifle was stored in my work shop for at least 1 hour prior to shooting, which is kept at 55 degrees F. Then the ammo was quickly loaded and shot outside within 5 min.


I will summarize the data below by including the following…

*******************************
Powder Type
Caliber
Load Data

Warm Group Temp
Warm Group Avg
Warm Group SD

Cold Group Temp
Cold Group Avg
Cold Group SD

Temp Difference
Avg Vel Difference



*********Here's the Data***********
THE USUAL DISCLAMERS APPLY WITH THE LOAD DATA.
!!WORK UP YOUR OWN LOADS FOR YOUR RIFLES!!
*****************************************************

Powder Type – H4350
Caliber – 6.5x47 Lapua
Load Data – 40.0gns, Lapua Case, CCI450, 140 Hybrid

Warm Group Temp = 70F
Warm Group Avg - 2781 fps
Warm Group SD – 1.8 fps

Cold Group Temp = 10F
Cold Group Avg - 2767
Cold Group SD – 10.5

Temp Difference – 60 Degrees
Avg Vel Difference – 15 fps


NOTE: Good SD's and Temp stability with H4350 and the 6.5x47. Most info I've read says about 0.3 FPS per degree of temp change, and that's about what I saw. No surprise here.



*****************************************************

Powder Type – H4350
Caliber – 6.5 Creedmoor
Load Data – 42.2gns, Lapua SRP Case, CCI450, 143 ELDX

Warm Group Temp = 70F
Warm Group Avg - 2676 fps
Warm Group SD – 23.1 fps

Cold Group Temp = 10F
Cold Group Avg - 2649
Cold Group SD – 11.5

Temp Difference – 60 Degrees
Avg Vel Difference – 27 fps


NOTES: The high SD on the Warm Group was mainly due to the very first shot, which was about 50 fps slower than the rest (not sure why). Also note that if you've ever heard of Small Rifle Primers being unreliable with large cases in cold weather, well… I had two rounds misfire on the Cold Group. One of them I tried again and it fired. The other never fired after 3 tries. The 27 fps difference over a 60 degree change is about 0.5 fps per degree. This seems a little high for H4350, but not out of the ordinary.


*****************************************************

Powder Type – H4350
Caliber – 300WSM
Load Data – 63.0gns, Norma Case, CCI250, 178 ELDX

Warm Group Temp = 70F
Warm Group Avg - 2916 fps
Warm Group SD – 18.6 fps

Cold Group Temp = 2F
Cold Group Avg - 2912
Cold Group SD – 9.2

Temp Difference – 68 Degrees
Avg Vel Difference – 4 fps

NOTE: I haven't finished load development with this rifle, but liked what I saw from the results above, so I reran the same test with a slightly lower charge weight. Results below.

*****************************************************

Powder Type – H4350
Caliber – 300WSM
Load Data – 62.5gns, Norma Case, CCI250, 178 ELDX

Warm Group Temp = 55F
Warm Group Avg - 2926 fps
Warm Group SD – 10.0 fps

Cold Group Temp = -5F
Cold Group Avg - 2912
Cold Group SD – 13.6

Temp Difference – 60 Degrees
Avg Vel Difference – 14 fps

NOTE: Still outstanding temp stability in the 300 WSM. I will be working in this range more to develop my hunting load for this rifle.


*****************************************************

Powder Type – RL26
Caliber – 7SAUM
Load Data – 59.2gns, Norma Case, CCI250, 180 VLD

Warm Group Temp = 70F
Warm Group Avg - 2870 fps
Warm Group SD – 5.6 fps

Cold Group Temp = 2F
Cold Group Avg – 2846 fps
Cold Group SD – 8.3

Temp Difference – 68 Degrees
Avg Vel Difference – 24 fps


NOTE: This rifle and load are very well proven for me (low SD's always consistent), so I have a lot of confidence in these numbers. RL26 looks to be about 0.35 fps per degree of temp change. Not bad at all for a powder that is not technically "Temperature Stable".


*****************************************************

Powder Type – 8028XBR
Caliber – 223 Rem
Load Data – 22.5gns, Hornady Case, CCI200, 69 TMK

Warm Group Temp = 70F
Warm Group Avg - 2729 fps
Warm Group SD – 23.8 fps

Cold Group Temp = 10F
Cold Group Avg – 2683 fps
Cold Group SD – 12.1 fps

Temp Difference – 60 Degrees
Avg Vel Difference – 46 fps


NOTE: This rifle and load are just for practicing out to 300 yds, so I don't take a lot of care in loading the ammo, which gives me higher SD's. However, it's apparent that the 8028XBR is effected by low temps quite a bit.


*****************************************************

Powder Type – RL19
Caliber – 300 WSM
Load Data – 66.0gns, Norma Case, CCI250, 200 ELDX

Warm Group Temp = 70F
Warm Group Avg - 2862 fps
Warm Group SD – 30.1 fps

Cold Group Temp = 10F
Cold Group Avg – 2823 fps
Cold Group SD – 24.9 fps

Temp Difference – 60 Degrees
Avg Vel Difference – 39 fps


NOTE: This load just doesn't shoot very well in my rifle, but I had a few rounds laying around from an early attempt at load development, so decide to shoot them. With such high SD's I wouldn't trust this data much, but it shows RL19 to be fairly temp sensitive, which is consistent with what most people say about it.



*****************************************************

Powder Type – N560
Caliber – 300 WSM
Load Data – Norma Case, CCI250, 178 ELDX

Warm Group Temp = 70F
Warm Group Avg - 2932 fps
Warm Group SD – 13.9 fps

Cold Group Temp = 4F
Cold Group Avg – 2847 fps
Cold Group SD – 14.9 fps

Temp Difference – 66 Degrees
Avg Vel Difference – 85 fps!!

NOTE: This was the big loser of this test. I lost 85 fps over a 66 degree temp change! I'm not loading any more of this N560.


*****************************************************

And now for the weirdest of the results…. VARGET, which actually sped up as it got colder…

*****************************************************

Powder Type – Varget
Caliber – 308 Win
Load Data – 45.0gns, Fed Case, CCI200, 165 Partition

Warm Group Temp = 70F
Warm Group Avg - 2699 fps
Warm Group SD – 12.9 fps

Cold Group Temp = 10F
Cold Group Avg – 2724 fps
Cold Group SD – 11.5 fps

Temp Difference – 60 Degrees
Avg Vel Difference – This load was 25 FPS FASTER with a 60 degree Drop in temp.


NOTE: I figured this test could not be right, so I ran it again the next day. Here's that data…


*****************************************************

Powder Type – Varget
Caliber – 308 Win
Load Data – 45.0gns, Fed Case, CCI200, 165 Partition

Warm Group Temp = 70F
Warm Group Avg - 2696 fps
Warm Group SD – 8.7 fps

Cold Group Temp = 2F
Cold Group Avg – 2716 fps
Cold Group SD – 13.5 fps

Temp Difference – 68 Degrees
Avg Vel Difference – This load was 20 FPS FASTER with a 68 degree Drop in temp???

NOTE: I don't understand the Varget results. Weird thing is I haven't shot this rifle/ammo for about a year. I had a bunch of round loaded for it that I remember developing in the summer time (so probably 80-90 degrees), and the boxes were labeled as having a velocity of 2660 fps. So I was surprised to see velocities around 2700 fps when I shot the warm group. Then even more surprised with I saw them speed up with single digits temps.


****************
Summary
****************

I mostly found that H4350 is fairly temp stable in the 0.2-0.4 fps per degree range. I also was pleased to find that RL26 was fairly temp stable. N560 was awful, as was 8028XBR (but I only use this for 223 practice ammo).

With regard to Varget getting faster as it gets colder, I am stumped by this. Maybe it has something to do with my specific barrel, or bullet combo. Not sure.

Hope the data is helpful to people.

I'm astounded N560 faired badly.

 

[mfk]

Powder Temp Stability Test – 8028XBR, Varget, H4350, RL19, RL26, N560


Really cold weather, plus boredom inspired me to conduct a fairly extensive powder stability test this weekend on several of my hunting rifles.


Rifle Specs…

300 WSM – 1:10 twist 20" Proof Carbon barrel
7 SAUM – 1:9 twist 26" Proof Carbon barrel
308 Win – 1:11.25 twist 20" Bartlein barrel
6.5 Creedmoor – 1:8 twist 22" Bartlein barrel
6.5x47 Lapua – 1:8 twist 26" Bartlein barrel (target rifle)
223 Rem – 1:8 twist 24" Bartlein barrel (target rifle)

Testing Procedure…
4-6 shots (usually 5) were shot with cold ammo/rifle, then 4-6 shots were shot with Warm ammo/rifle. Speeds were recorded with a Labradar, and I did not delete ANY of the shots, so any outliers were left in the data. Cold ammo was left out overnight with Temps around -5 to +5 degrees F. Actual temp was recorded at the time of shooting the Cold Group. For Cold group shooting the rifle was left outside for at least an hour for the bore to get cold. Warm Groups were shot with ammo that was left in my house at 70 degrees F, and the Rifle was stored in my work shop for at least 1 hour prior to shooting, which is kept at 55 degrees F. Then the ammo was quickly loaded and shot outside within 5 min.


I will summarize the data below by including the following…

*******************************
Powder Type
Caliber
Load Data

Warm Group Temp
Warm Group Avg
Warm Group SD

Cold Group Temp
Cold Group Avg
Cold Group SD

Temp Difference
Avg Vel Difference



*********Here's the Data***********
THE USUAL DISCLAMERS APPLY WITH THE LOAD DATA.
!!WORK UP YOUR OWN LOADS FOR YOUR RIFLES!!
*****************************************************

Powder Type – H4350
Caliber – 6.5x47 Lapua
Load Data – 40.0gns, Lapua Case, CCI450, 140 Hybrid

Warm Group Temp = 70F
Warm Group Avg - 2781 fps
Warm Group SD – 1.8 fps

Cold Group Temp = 10F
Cold Group Avg - 2767
Cold Group SD – 10.5

Temp Difference – 60 Degrees
Avg Vel Difference – 15 fps


NOTE: Good SD's and Temp stability with H4350 and the 6.5x47. Most info I've read says about 0.3 FPS per degree of temp change, and that's about what I saw. No surprise here.



*****************************************************

Powder Type – H4350
Caliber – 6.5 Creedmoor
Load Data – 42.2gns, Lapua SRP Case, CCI450, 143 ELDX

Warm Group Temp = 70F
Warm Group Avg - 2676 fps
Warm Group SD – 23.1 fps

Cold Group Temp = 10F
Cold Group Avg - 2649
Cold Group SD – 11.5

Temp Difference – 60 Degrees
Avg Vel Difference – 27 fps


NOTES: The high SD on the Warm Group was mainly due to the very first shot, which was about 50 fps slower than the rest (not sure why). Also note that if you've ever heard of Small Rifle Primers being unreliable with large cases in cold weather, well… I had two rounds misfire on the Cold Group. One of them I tried again and it fired. The other never fired after 3 tries. The 27 fps difference over a 60 degree change is about 0.5 fps per degree. This seems a little high for H4350, but not out of the ordinary.


*****************************************************

Powder Type – H4350
Caliber – 300WSM
Load Data – 63.0gns, Norma Case, CCI250, 178 ELDX

Warm Group Temp = 70F
Warm Group Avg - 2916 fps
Warm Group SD – 18.6 fps

Cold Group Temp = 2F
Cold Group Avg - 2912
Cold Group SD – 9.2

Temp Difference – 68 Degrees
Avg Vel Difference – 4 fps

NOTE: I haven't finished load development with this rifle, but liked what I saw from the results above, so I reran the same test with a slightly lower charge weight. Results below.

*****************************************************

Powder Type – H4350
Caliber – 300WSM
Load Data – 62.5gns, Norma Case, CCI250, 178 ELDX

Warm Group Temp = 55F
Warm Group Avg - 2926 fps
Warm Group SD – 10.0 fps

Cold Group Temp = -5F
Cold Group Avg - 2912
Cold Group SD – 13.6

Temp Difference – 60 Degrees
Avg Vel Difference – 14 fps

NOTE: Still outstanding temp stability in the 300 WSM. I will be working in this range more to develop my hunting load for this rifle.


*****************************************************

Powder Type – RL26
Caliber – 7SAUM
Load Data – 59.2gns, Norma Case, CCI250, 180 VLD

Warm Group Temp = 70F
Warm Group Avg - 2870 fps
Warm Group SD – 5.6 fps

Cold Group Temp = 2F
Cold Group Avg – 2846 fps
Cold Group SD – 8.3

Temp Difference – 68 Degrees
Avg Vel Difference – 24 fps


NOTE: This rifle and load are very well proven for me (low SD's always consistent), so I have a lot of confidence in these numbers. RL26 looks to be about 0.35 fps per degree of temp change. Not bad at all for a powder that is not technically "Temperature Stable".


*****************************************************

Powder Type – 8028XBR
Caliber – 223 Rem
Load Data – 22.5gns, Hornady Case, CCI200, 69 TMK

Warm Group Temp = 70F
Warm Group Avg - 2729 fps
Warm Group SD – 23.8 fps

Cold Group Temp = 10F
Cold Group Avg – 2683 fps
Cold Group SD – 12.1 fps

Temp Difference – 60 Degrees
Avg Vel Difference – 46 fps


NOTE: This rifle and load are just for practicing out to 300 yds, so I don't take a lot of care in loading the ammo, which gives me higher SD's. However, it's apparent that the 8028XBR is effected by low temps quite a bit.


*****************************************************

Powder Type – RL19
Caliber – 300 WSM
Load Data – 66.0gns, Norma Case, CCI250, 200 ELDX

Warm Group Temp = 70F
Warm Group Avg - 2862 fps
Warm Group SD – 30.1 fps

Cold Group Temp = 10F
Cold Group Avg – 2823 fps
Cold Group SD – 24.9 fps

Temp Difference – 60 Degrees
Avg Vel Difference – 39 fps


NOTE: This load just doesn't shoot very well in my rifle, but I had a few rounds laying around from an early attempt at load development, so decide to shoot them. With such high SD's I wouldn't trust this data much, but it shows RL19 to be fairly temp sensitive, which is consistent with what most people say about it.



*****************************************************

Powder Type – N560
Caliber – 300 WSM
Load Data – Norma Case, CCI250, 178 ELDX

Warm Group Temp = 70F
Warm Group Avg - 2932 fps
Warm Group SD – 13.9 fps

Cold Group Temp = 4F
Cold Group Avg – 2847 fps
Cold Group SD – 14.9 fps

Temp Difference – 66 Degrees
Avg Vel Difference – 85 fps!!

NOTE: This was the big loser of this test. I lost 85 fps over a 66 degree temp change! I'm not loading any more of this N560.


*****************************************************

And now for the weirdest of the results…. VARGET, which actually sped up as it got colder…

*****************************************************

Powder Type – Varget
Caliber – 308 Win
Load Data – 45.0gns, Fed Case, CCI200, 165 Partition

Warm Group Temp = 70F
Warm Group Avg - 2699 fps
Warm Group SD – 12.9 fps

Cold Group Temp = 10F
Cold Group Avg – 2724 fps
Cold Group SD – 11.5 fps

Temp Difference – 60 Degrees
Avg Vel Difference – This load was 25 FPS FASTER with a 60 degree Drop in temp.


NOTE: I figured this test could not be right, so I ran it again the next day. Here's that data…


*****************************************************

Powder Type – Varget
Caliber – 308 Win
Load Data – 45.0gns, Fed Case, CCI200, 165 Partition

Warm Group Temp = 70F
Warm Group Avg - 2696 fps
Warm Group SD – 8.7 fps

Cold Group Temp = 2F
Cold Group Avg – 2716 fps
Cold Group SD – 13.5 fps

Temp Difference – 68 Degrees
Avg Vel Difference – This load was 20 FPS FASTER with a 68 degree Drop in temp???

NOTE: I don't understand the Varget results. Weird thing is I haven't shot this rifle/ammo for about a year. I had a bunch of round loaded for it that I remember developing in the summer time (so probably 80-90 degrees), and the boxes were labeled as having a velocity of 2660 fps. So I was surprised to see velocities around 2700 fps when I shot the warm group. Then even more surprised with I saw them speed up with single digits temps.


****************
Summary
****************

I mostly found that H4350 is fairly temp stable in the 0.2-0.4 fps per degree range. I also was pleased to find that RL26 was fairly temp stable. N560 was awful, as was 8028XBR (but I only use this for 223 practice ammo).

With regard to Varget getting faster as it gets colder, I am stumped by this. Maybe it has something to do with my specific barrel, or bullet combo. Not sure.

Hope the data is helpful to people.

The Varget speed increase at lower temp really is weird.
Thanks for sharing the data! There is no "I" in team