Powder Temp Stability Chart

[choprzrul]

This is something I put together for my own quick reference and in no way should be taken as gospel....or accurate....or reliable as I plagerized the heck out of www sources for most of it. Every rifle/cartridge/powder/bullet/environmental combination will be different and produce variances to (rifle in particular) powder temp stability!

Excel file: Temp Stability.xls

But.....I thought perhaps some of you might find it useful, so I am sharing. If you have any info for filling in the blanks, please share. The Excel file has notation included for de-coppering agent also. I'm kinda thinking about adding the ranking numbers for burn rate also....maybe down the road if I get time?

Here is a quick and dirty version of the Excel file linked above:

Powder Velocity Change per Degree

Accurate
AA2460 0.29 fps per *
AA2520 0.74 fps per *
AA3100 0.90 fps per *
AA4064 1.11 fps per *
AA4350 0.35 fps per *
Magpro 1.01 fps per *
AA1680
AA2015
AA2200
AA2230
AA2495
AA2700
AA5744
Nitro 100
Solo 1000
Solo 1250

Alliant
AR Comp 0.77 fps per *
PP2000MR 0.99 fps per *
RL10x 0.71 fps per*
RL12 0.21 fps per *
RL15 1.52 fps per * from 50* and up
RL16 0.34 fps per *
RL17 1.42 fps per *
RL19 1.18 fps per *
RL22 1.16 fps per *
RL25 1.59 fps per *
RL26 0.50 fps per *
Varmint 0.89 fps per *
RL7
RL23
RL33
RL50

Hodgdon
Benchmark 0.44 fps per *
CFE223 1.72 fps *
H1000 0.21 fps per *
H110 1.24 fps per *
H380 1.44 fps per *
H414 1.42 fps per *
H4350 0.12 fps per *....also see source @ .29
H4831 0.36 fps per *
H4831 SC 0.08 fps per *
H4895 0.23 fps per *
H50 BMG 1.64 fps per *
HS-6 1.21fps per *
Hybrid 100v 0.78 fps per *
Lil' Gun 1.31 fps per *
Retumbo 0.49 fps per *
Superformance 1.21 fps per *
US869 1.68 fps per *
Varget 0.13 fps per *
H4227
H4198
H322
H335
H4895
BL-C2
H4350

IMR
IMR3031 0.73 fps per *
IMR4064 0.53 fps per *
IMR4166 0.45 fps per *
IMR4227 1.17fps per *
IMR4320 1.32 fps per *
IMR4350 0.64 fps per *
IMR4451 0.32 fps per *
IMR4831 1.19 fps per *
IMR4895 0.87 fps per *
IMR7828 1.36 fps per *
IMR8208xbr 0.59 fps per *
IMR4198
IMR4007
IMR4955
IMR7977
IMR7828

Norma
N203B 0.50 fps per *
N200
N201
N202
N204
MRP
URP

Ramshot
Big Game 0.98 fps per *
Hunter 0.86 fps per *
Magnum 0.87 fps per *
TAC 0.91 fps per *
X-Terminator
Wild Boar

Vihtavuori
N140 0.40 fps per *
N150 1.08 fps per *
N160 1.24 fps per *
N550 0.39 fps per *
N560 0.97 fps per *
N104
N110
N125
N130
N133
N135
N540
N530
N165
N565
N170
N570

Winchester
StaBALL 6.5
W296 1.24 fps per *
W748 1.32 fps per *
W760 1.42 fps per *
W780

[RugerNo1]

Do these numbers take into account REVERSE temp stability?

Some powders get faster as ambient temps cool down.

[choprzrul]

Do these numbers take into account REVERSE temp stability?

Some powders get faster as ambient temps cool down.

**EDIT**......I just re-read your question.....what powder gets faster as temperatures drop??


I would think it is a fairly consistent ratio. Load development done at 70 degrees here in CA.....and then shooting at 20 degrees on a deer or elk hunt will have (50 degrees X fps variance) velocity drop.

Let's say you have a 308 shooting 2750fps at 70 degrees. At 1.32 fps per degree, that leaves you with 2684 fps at 20 degrees. Using the Hornady 165gr BTSP at .435 BC and a 150 yard zero, it gives me about 2" more drop at 400 yards and 4" more at 500.

Not a lot, but worth considering when choosing powders IMHO.

.

[J-cat]

Much of it is wrong because the individuals testing the powder didn’t know what they were doing.

[choprzrul]

Examples?

I'm all about having accurate numbers. Please provide any and all accurate data that you have and I'll update OP.

.

[J-cat]

For example, in my 308 both CFE and 2000MR are under .6 FPS per *. IMR4064 is under .4 FPS per *. Staball is under .3 FPS per * with 140 grain bullets in my 6.5 Creedmoor. But I fine tuned these loads so my charge weight and coal fall in the middle of the accuracy node. That’s how you minimize the weather’s effect on ballistics.

Also, temperature stability depends on the cartridge. What’s stable in one may not be stable in another.

[RugerNo1]

[choprzrul]

Some powders will slow down as the temperature goes up. This usually applies to pistol/shotgun powders (perhaps only when used in those firearms), which a couple are referenced in the OP. A few I am aware of are:

- WST
- Promo
- Solo 1000
- SR7625
- Universal
- WSF
- Silhouette

I don’t have anything but personal experiences of many fellow USPSA shooters to back up this info and I am aware you’re referencing rifle powders mostly, but your inclusion of some pistols powders encouraged my comment.

Ah...pistol powders. I should have specified this was about rifle powders. Some of the powders I listed I just copied out of my list of powders in QuickLoad.

Thinking about this....I had previously been under the impression that physics and chemistry dictated that as temperature of powder increases, its associated burn temps and pressures would also increase.
.

[ar15barrels]

This is something I put together for my own quick reference and in no way should be taken as gospel....or accurate....or reliable as
I plagerized the heck out of www sources for most of it.
Every rifle/cartridge/powder/bullet/environmental combination will be different and produce variances to (rifle in particular) powder temp stability!

Without using the same cartridge and test conditions, none of the numbers are comparable.
You could test the same cartridge with the same powder and different bullets and see dramatically different velocity variations.
What you really should be comparing is PERCENTAGE of variation.

You would do FAR better to compare loads in Quickload to see how much velocity variation you will get with temperature change.

[J-cat]

Also, people need to understand that in terms of accuracy ball rifle powders do better at max pressures. So when you slap together a medium book load without first doing a full workup, and then write internet articles on how stable or unstable a powder is, then well you’re just showing people how stupid you are. Trouble is then other people take that info and run with it and create charts and tables.

Then there’s the actual test. I freeze my rounds and boil my rounds and take them to the range on ice and in a thermos. I take the temperature of the liquid before shooting and I test accuracy, velocity, and zero at three different temperatures.

With 175SMK and CFE in the 308 there’s hardly any velocity change between 30 and 70 degrees and nearly all the velocity gains occur from 70-120 degrees. Not to worry, the zero shifts to offset the velocity increase. So you don’t notice anything downrange.

I see a table showing 1.72 FPS per degree I get mad.

[slamfire1]

You know, I don't know what data the Quickload guys used to create their models, so who is to say that their algorithm's reflect reality.

And then, powder stocks vary. They vary so much that lifetimes vary significantly:



so who has done a temperature spread versus gunpowder deterioration study? By the way, pressures spike with deteriorated gunpowder as the burn rate is unpredictable.

If we had cheap, portable, pressure testing equipment we could be seeing patterns that are actually there. But, I don't have anything like that.

While I appreciate the OP's work and intent, based on my experience, develop your loads in 70's and 80's F weather. Then go out and shoot, and expect blown primers when temperatures reach the 90's. Even though you did everything from monitoring primers, measuring velocities, when developing loads. Future shooting of those loads will lead to cutting your powder charges, and a continuation of cutting, till the over pressure indications go away. And by the time you have a load which is accurate, predictable, and you are not blowing or piercing primers, you will be puzzled why in print values, and internet claims, are so much higher than what you are getting out of your thunderstick.

[J-cat]

I blew a primer once... when I seated a BarnesX bullet too close to the lands.

[slamfire1]

I blew a primer once... when I seated a BarnesX bullet too close to the lands.

I am not shooting F Class at 1000 yards so I seldom push to the maximum. And like your experience, where just a little OAL leads to a blown primer, I prefer ammunition that allows a little more slop before going over pressure.

Load maximum loads, any change will cause pressure problems. And that includes lot differences between powders.

[J-cat]

When I say max I mean book max, not sticky bolt max.

I have been doing these temperature tests for many years and have never blown a primer and the round is so hot you can’t hold it in your hand. Loading to maximum pressure will not lead blown primers unless you are too close to the lands or use too fast of a powder for a particular bullet weight. For example, loading a max charge of CFE under a 208 touching the lands will blow primers in the heat. But not with 175s. Book max typically has a 1gr cushion built in before you get sticky bolt. That cushion is what prevents blown primers in the heat. The problem with people is they always want to hotrod their rifle and turn it into something it isn’t. Or they chase lands hoping to get benchrest accuracy out of their crappy rifles. These two behaviors are the primary cause of hand load problems.

[choprzrul]

Very interesting and educational dialog has developed.....I'm glad I started this thread!!

.