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

[odoylerules]

I'm super surprised about the N560. I thought those were really stable powders

 

[Idaho Trecker]

I'm super surprised about the N560. I thought those were really stable powders

I also thought that too. I know Shawn at defensive edge did a bunch of testing on n570 and had excellent results. It's on his site also.

 

[Gary in MD]

I use N160 a lot
Has anyone done any testing on it's temperature stability?

 

[jamiebolseth]

N560 is one of the reasons I did this test. I was working on a load for my shiny new 300 wsm at Christmas time and got good velocity and accuracy with it just in time for a NM oryx hunt a couple of weeks ago. Then I went out on a cold day to shoot it at distance right before I left for the trip and was hitting 6-8 inches low at only 600 yds (didn't have the Labradar that day). Confidence was shaken and the only thing I could think of was the low temps. So I took my 7 Saum (which I know well) for the oryx trip and decided to come back to the 300 wsm when I had more time to test.

So in my 300 WSM N560 is a problem with cold temps. That's all I can tell you.

Jamie Bolseth

FYI - a 7 Saum will kill an Oryx!

 

[Pdvdh]

Neat! I've done some temp sensitivity testing and it's time intensive.

Thanks much for sharing your efforts.

I valued the RL26 data, as that's a powder I use in 2 hunting rifles. BTW, my temp sensitivity data is similar, with RL26.

 

[DEW]

Great info. Thanks for sharing your results.

 

[Canhunter35]

Great info, thanks for sharing. I believe I've read that Hodgdon coats the extreme powders in something that offsets the declining burn rate in cold temp and maybe the coating is really offsetting the varget to the point it's picking up speed?
I've had good luck with varget and h4350 in cold temp, but if you get down to -30f to -35f then velocities can drop within the neighbourhood of 150fps

 

[bpotter]

Great test. I have seen H4831 faster in cold temps or maybe it's slower LLP in warm temps by 20 fps.

 

[brentc]

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 – 2855 fps
Cold Group SD – 8.3

Temp Difference – 68 Degrees
Avg Vel Difference – 24 fps

2870 - 2855 = 15 not 24

Did I miss something?

 

[jamiebolseth]

2870 - 2855 = 15 not 24

Did I miss something?

Sorry. Just checked my data and I mistyped it. It was 2870 - 2846. Updating the original post.


Typing is hard.

 

[brentc]

Thanks for your observations. It's nice to see actual testing vs relying on labels.

 

[Bob Wright]

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.

This is a lot of work to run these tests. Good stuff!
I was told by Alliant that RL 23 has surprised Alliant as it also increased speed at lower temps. I expect to run my tests soon. Will have to refrigerate my ammo and shoot, living in the low desert. I will be shooting 7mmREM mag with 175 Noslers, Fed 215 primers. I know at 70° F its shoots 2920 FPS, 7 SD. No pressure signs here, but since posted data doesn't represent this load, I am a bit concerned I might see pressure.

 

[jamiebolseth]

The Varget results are strange to me, so I decided to spend 5 min. Googling about it. I found this quote from a 2013 post on Snipers Hide..

"When Varget was first announced, Hodgdon published a little pamphlet handout that reported temp/velocity variances. Velocities were essentially constant from the high end on down to the lowest, except that at the very lowest (below 0 degrees F.), there was a small UPtick in velocity."


There's clearly something to the Varget increase in velocity with a drop in temps....

 

[Rhovee]

I always like seeing info like this. I wish AB would start testing powder along with bullets.