Is there a temp sensitive powder list or chart

hitch.bd

hitch.bd

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So far I have come across two powders that are temp sensitive. IMR4320 and IMR 4831. In both cases I worked up loads when it was cold and then later when it was warm the recoil was extremely violent. I have since switched to IMR 4350 for my 30.06 and am wondering about what to change to for my 7mm mag.
has anyone else come across temp sensitive powder?
How can we avoid this in the future?
regards, Hitch
 
Depends on what you consider temperature sensitive...

The only powders I have found to be exceptionally temperature insensitive are the ones that are made in Australia and have green kernels. By this, I mean the Hodgdon Extreme line, mostly. The new IMR8208 is reported to be one of the best yet (also green kernels from Australia). Have 8 lbs., but have not tried it yet.
 
kombayotch said:
Depends on what you consider temperature sensitive...

The only powders I have found to be exceptionally temperature insensitive are the ones that are made in Australia and have green kernels. By this, I mean the Hodgdon Extreme line, mostly. The new IMR8208 is reported to be one of the best yet (also green kernels from Australia). Have 8 lbs., but have not tried it yet.
Click to expand...

What cal's are imr 8208 good for? never heard of it
 
H-4831, H-1000, and Retumbo (with heavy bullets) are probably the most stable.
RL-15,RL-17, RL-19, RL-22, and RL-25 are more temperature stable than the powders you listed....at least I have never had an issue with them. RL-19, 22, and 25 should work well in you 7Mag.

The powders you had trouble with are old technology.
I don't use them anymore.
 
I've tested RL-17 and RL-25 and they are not very temperature stable. The US military moved away from RL-15 in their long range loads due to poor temperature stability. They moved to IMR-4064, which is old technology.

The Alliant stuff is like the VV N500 series; good velocity and accuracy, but at the expense of temperature stability. Anything that is double based is unlikely to be temperature stable.
 
I found RL-22 to be quite sensite. Went from having a good accurate load one day to freezing the bolt on that same rifle in hot weather....primer just flopped out of the pocket when I finally got to it.

I still use it as its a great powder...I just wont bother using when its above 25C outside.
 
Above 80 degrees Fahrenheit all powders are temperature sensitive including the Extreme stuff.

RL-15 was dropped because of the desert wars and 120 degree temperatures.
Supposedly ammo left in the cab of a Hummer can hit 150 degrees....Which creates some issues when you fire that round!

I have a lot of experience with RL-15 and few other powders at this burn rate produce accuracy at top velocity so temperature instability (at high temperatures) is somewhat of a trade off.
I have found that accuracy (within reason) does not seem to be affected by the change in velocity.

The Reloader powders vary considerably from lot to lot...Something to be aware of.
 
80F isn't even 27C. The Extreme line is stable well beyond that...

Automitive standards for passanger cars require components to withstand 80C temperatures inside the passenger compartment. That is 176F!
 
Try the Hodgdon Data center: http://data.hodgdon.com/cartridge_load.asp

You might want to look at H1000. It was selected by the US military for their new long range 300 WM load because of its temperature stability:
https://www.neco.navy.mil/upload/N00164/N0016409RJN30000209RJN30_0002_att.pdf

I've temperature tested it myself (have pressure testing equipment), and found it to be incredibly temperature stable:

6mm_Crusader_T2.jpg

6mm Crusader is basically a .224 Mashburn Improved... similar to 6mm AI


Piece of advice: H1000 has a thick coating and really benefits from a magnum primer.

.
 
Far too much is being made of temperature sensitive powder. For a hundred years of smokeless powder shooting it wasn't even heard of.
If you go out in cold weather and get a load that is .5 grain below bolt stick, you are likely in for trouble, if you use it in hot weather.
However, factory loaded ammunition does not carry a sticker, stating what temperature it is good for, or what temperatures would be dangerous.
Just do normal loadings and forget about what temperature it is.
One strange thng I have noticed, however, is that it is the modern reloaders, using modern loading manuals, which are in general, light loadings, are the very people worrying about temperature change!
 
Those who don't shoot long range and/or don't rely on first round hits, seldom worry about velocity change over temperature. If all your shooting is at short distances, or you have the benefit of sighter shots, then no, I guess you really wouldn't understand the importance of temperature stability and would believe the concern has something to do with safety.
 
Well the old rule of thumb was to work up your loads in warm weather. That way a max load would be OK in cooler temps. A max load worked up in cool weather is likely to exhibit pressure indicators in warm weather. It probably does'nt need to be any more complicated than that, even with so-called "old technology" propellants which have been chugging away quite nicely since the early 1930s.

It's fascinating to see a 70 yr old " Shooter's Bible" which lists all of DuPont IMR 4227,4759,3031,4198,4064,4320(developed for .30-06 match ammo with a 180gr bullet), as well as Herco Unique,2400 and Bullseye. You still don't need to look much further. The US Army used billions of rounds of .30-06 and 7.62 with IMR4895 under various climatic extremes around the world and it seemed to have worked out quite well. The Brits used tons of WRA contract .303 ammo in WW2 which used a predecessor of today's BLC2 and that seemed OK too.
 
hitch.bd said:
So far I have come across two powders that are temp sensitive. IMR4320 and IMR 4831. In both cases I worked up loads when it was cold and then later when it was warm the recoil was extremely violent. I have since switched to IMR 4350 for my 30.06 and am wondering about what to change to for my 7mm mag.
has anyone else come across temp sensitive powder?
How can we avoid this in the future?
regards, Hitch
Click to expand...

Did you chronograph your loads or have any other way of testing them, otherwise the increased recoil might be just the difference of shooting with a few layers of clothes and a parka in the cold to now shooting with a t-shirt and a light jacket. If you are reloading within the limits of a newer manual there shouldn't be a problem.
 
kombayotch said:
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You might want to look at H1000. It was selected by the US military for their new long range 300 WM load because of its temperature stability:

I've temperature tested it myself (have pressure testing equipment), and found it to be incredibly temperature stable:
.......
.............
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Click to expand...

I run H-1000 in my long range 338Edge.
Its an amazing powder with single digit variation to go along with the stability.

I give up over 100fps with the 300SMk just to use it.

Doesn't work as well in some other guns though.
 
Kind of nice data with the pressure equipment. The only two powders I've had experiences with that were probably due to temperature were IMR 4320 and RL15. I actually thought the 4320 might have been the result of some kind of excursion effect it was so severe. There was no potential for a double load either. Just to add a bit more. The second experience was with a 7 BR, where I froze a bolt in very hot August weather using a load I found useful at moderate temperatures, i.e. 60 -70 degrees F. The experience made me realize that size of the case really matters. In other words, a change of 0.5 grains is a much bigger change in a 7 BR case than it is in a 3006 case. At least that is the way I have come to think of it. The first experience was with a 6.5 Swede and I've been a bit scared of 4320 ever since.
 
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