Temperature sensitivities for powders

GL & 204 Thanks for this info .OK ,so if it is 50 degrees colder then 50 x 1.72 fps slower .That is not going to make a bunch of difference if I am getting this right ? 86 FPS slower. Thank you both
 
I am very good friends with the Hodgdon family and I have a couple of friends that work at Hodgdon powder company. I have asked the same question about temp sensitive powders. Their answer in short is, any Hodgdon "extreme" powder or any IMR "enduron" powder is temp stable. Other powders that are not in the Extreme or Enduron lines will be effected more by temperature swings. Also, all temp stable powder is an extruded powder. However, not all extruded powder is temp stable. I can't speak for other powders out there since I only use Hodgdon and IMR. Hope this helps a little.
 
BLC2 is not a cold weather powder and found that the hard way. Shot great in the fall working on a load. Come coyote season I was key howling but it was -10.

All my coyote loads are extreme loads. When it gets real cold, like -20, even they seem to lose a little bit.
 
Originally Posted By: HunterLee BLC2 is not a cold weather powder and found that the hard way. Shot great in the fall working on a load. Come coyote season I was key howling but it was -10.

All my coyote loads are extreme loads. When it gets real cold, like -20, even they seem to lose a little bit.


If you're key holing it's not the powder and most likely not related to the decrease of velocity although that could play a small roll. More than likely it was the drop in temperature as that plays a larger role in stability than 100fps or so in velocity loss.

Most likely your bullet was on the ragged edge of stability and the temperature drop threw it out. The lower the temperature the lower your stability factor will be. Berger has a handy stability calculator that you can play around with by entering your bullet info and twist rate (always best to measure yours since they can easily vary as much as .5"). It's a nice tool to check out.
 
I used CFE223 and BL-C2 in .22-250 and .223 last season, based on that chart it seems pretty accurate. I also noted that CFE appears to be the same powder compound as the BL, but modified with tin oxide? for copper dispersion. I answered my own questions about these in cold weather, so I have gone back the Extreme variety. In .280 Remington, RL19 and RL22 also exhibited some velocity loss in cold weather, typically near zero* or below.
 
i wonder if those numbers in the charts from the 65g forum are caliber and barrel length specific or not?



still a neat reference for comparing sensitivity though as a rough gauge at the very least
 
blc-2 will spike in warm temps if you work up loads in the fall or winter and shoot in the summer.worked up some .223 loads for coyotes temps at testing around 40 degrees and about .05 under max hogden load data.went sage rat shooting at 90-92 degrees and pierced primers.
 
Originally Posted By: wileCSo I would assume the FPS numbers you get from a reloading manual would be a regulated temp of say 70 degrees?
As good an assumption as any,,, works for me.
 
hornady doesnt list that data in their books that i can see, but i'm sure a quick note to tech support would get the info.
 
I have heard about temperature sensitive powder since I started reloading. That was about 1966! I have never run into a problem that I'm aware of with any powder. I suspect temp can make a difference but I have never noticed it. I have never loaded and worked up loads in freezing weather, I like spring weather for working up loads. I have never hunted in weather in the 90+ range either. Make's me sweat to much. I just don't see this as being the problem it's made out to be but I do guarantee you one thing. You think you need it and someone is gonna develop it for you for a price! Manufacturer's are much more tuned into what you want than what you really need!
 
I worked up a load (as recommended in Bob Hagel's book on practical ballistics for the N. American Hunter) which was on the upper end of the charts. Actually, exceeding the charts and managed to blow primers and seize the bolt on a Remington 788 .223. I worked up the load in the winter and shot in July using W748 powder. I'll never do that again.
 
Originally Posted By: Don FischerI have heard about temperature sensitive powder since I started reloading. That was about 1966! I have never run into a problem that I'm aware of with any powder. I suspect temp can make a difference but I have never noticed it. I have never loaded and worked up loads in freezing weather, I like spring weather for working up loads. I have never hunted in weather in the 90+ range either. Make's me sweat to much. I just don't see this as being the problem it's made out to be but I do guarantee you one thing. You think you need it and someone is gonna develop it for you for a price! Manufacturer's are much more tuned into what you want than what you really need!

So you have never worked up a load in the winter or shot in 90+ degree weather but say that temp tolerant powder is not an issue. I have done both and can tell you that some are real sensitive to temperature fluctuations.
 
Those of us older folks learned a long time ago that it is best to have a hot weather load and a cold weather load, and ask God for the Common sense to know the difference.

I and partners shot 748,335, Win 760, and AA2700 going from 75*-100*, but we knew how to deal with it, the bonus was long barrel life.

Old time favorites like IMR 3031,4895, 4064, 4350 all had at least a .5g pressure spike, so backing off the load a tad was always in order for red hot dog towns...literally.

So, Hellgate, you know how all of old pharts dealt with this through the years. It takes shooting a rifle in the Winter, then again in the Summer recording loads and we used an Ohler 33. The accuracy node was usually at a particular speed.

So, to make the load development easy, we backed off the COLD weather load 2.0--2.5g in hot weather and worked up. When we hit the Winter time accuracy(speed), Accuracy was back again!!! Dumb butt simple! This aint even close to rocket science.

Now, for all of those that have drank the Kool Aid that the NON temp sensitive powder are not sensitive to hot and cold weather...well, You are probably not using a chronograph and shooting very small groups.

If I were out to get a one load do all, I would go to the Enduron series of powders, and look no further. I have found that H4895, Varget, and H4350 do vary from very cold to very hot weather(32-95*) when you are looking for bug hole groups. Varget burns ungodly hot, another issue when it comes to cleaning hard cooked on carbon out of the barrel .

There is a heat index for various powders, and I hope you will take this index to heart as it is will bring front and center how a powder choice will burn up a barrel quicker/slower. Don't confuse the burning rate chart with heat index chart.

Learning to reload is a life time hobby with all of it's various tid bits of information that will add to your education of being your own
ballistician.
 
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Originally Posted By: reb8600Originally Posted By: Don FischerI have heard about temperature sensitive powder since I started reloading. That was about 1966! I have never run into a problem that I'm aware of with any powder. I suspect temp can make a difference but I have never noticed it. I have never loaded and worked up loads in freezing weather, I like spring weather for working up loads. I have never hunted in weather in the 90+ range either. Make's me sweat to much. I just don't see this as being the problem it's made out to be but I do guarantee you one thing. You think you need it and someone is gonna develop it for you for a price! Manufacturer's are much more tuned into what you want than what you really need!

So you have never worked up a load in the winter or shot in 90+ degree weather but say that temp tolerant powder is not an issue. I have done both and can tell you that some are real sensitive to temperature fluctuations. Most definetly so. Found that out using AA2520. May not be such an issue on deer sized game or larger, but on coyote and smaller . Yes.
 
Varget and H4895 eats barrels like you are shooting battery acid, special purpose powders only!!!!


Seems like no body has any common sense these days!
 
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Originally Posted By: reb8600Originally Posted By: Don FischerI have heard about temperature sensitive powder since I started reloading. That was about 1966! I have never run into a problem that I'm aware of with any powder. I suspect temp can make a difference but I have never noticed it. I have never loaded and worked up loads in freezing weather, I like spring weather for working up loads. I have never hunted in weather in the 90+ range either. Make's me sweat to much. I just don't see this as being the problem it's made out to be but I do guarantee you one thing. You think you need it and someone is gonna develop it for you for a price! Manufacturer's are much more tuned into what you want than what you really need!

So you have never worked up a load in the winter or shot in 90+ degree weather but say that temp tolerant powder is not an issue. I have done both and can tell you that some are real sensitive to temperature fluctuations.

Yep, just about any Ball powder comes to mind. A Max load of H335 developed in 50 degree weather sure does change in 92 degree summer heat.
 
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