Temp sensitive?

For you guys that often hunt in 80-110 F weather I get why you would have two loads. Up here, the warmest hunting temperature we will see is 60F at mid day. Far more common to be - something. The temp unstable powders are effected in high heat, but they are also severely affected by extreme cold. It would not be uncommon to loose 300 fps going form +50F to -30 F using one of the RL powders and it gets worse the colder it gets after -30. Getting an extra 100 fps at +50F isn't very helpful when you drop 300 FPS from one day to the next. It is not unusual to go from 0 to -35 overnight. The Extreme powders move less than 75 FPS in the same conditions.

For target loads that you are loading to conditions, I can see using RL and others like it if that is what gives you maximum performance. For a hunting load, consistency to me is paramount. Has to go bang every time and it needs to hit within an inch at 300 yards over a trips common temp range. I don't want to have to re-sight my hunting rifles as I change loads for various temperature conditions or with the same load because it got cold and the velocity dropped 200 FPS. Especially when you are shooting 5-800 or more yards, consistent velocity is required for ballistic solutions to work properly. I often think that hunters have allowed target considerations to over influence their hunting loads. Especially at the longer ranges, more consistency, even at a little lower velocity is far preferable in a hunting load than being at the ragged edge for performance but everyone's situation is different so I get why others think another way.
 
Last edited:
I use a LabRadar for my long range shooting sessions. I shoot Retumbo, H1000, Varget, and RL33 and log velocities for just about every shot. I haven't noticed a difference between winter and summer in AZ, but I don't let the bullets bake in the sun too long either.
 
I basically target shoot here in Kansas mostly in spring and fall temps 50-90 degrees what powders do you all recommend . I shoot 223, 264 wm, 6.5 creedmoor and 300 wsm now. I shoot 8208, 223 CFE, H4350, and Varget for the most part. Got some 6.5 Stabill (?) haven't used any of it when 4350 wasn't around. Any other suggestions. Also have some Superformence when I had a 300wsm few years back. If I pick up another caliber may be 280 AI or PRC 6.5 or 300. I am getting a little old and can't hunt much anymore.
 
Last edited:
JE,
On that thought, I feel that changing the charge to compensate for the temperature to get the same velocity may even effect accuracy. I can't tell if its a hunch at this time or if I'm paranoid.


I'm often accused of being paranoid/anal and can except that because my experiences have been that any change can and will normally effect the performance in any load. I have tried to increase or decrease powder charge to match the velocity of one of my favorite loads and even though it was close to the same performance. It did not match the original load accuracy, and some times it was actually slightly better but other times it was slightly worse.

All I can think of is that the addition of more less powder, can change the burn time even though it is the same batch number. The bench rest guys could probably explain why better because they try to eliminate the human error in shooting by not touching the rifle while firing. It is very hard to find a .050 thousandths accuracy change doing the kind of shooting we do and at some point many don't worry about such small changes.

In over 50 years of reloading, I have never been able to exactly duplicate velocity and accuracy of any load no matter what I did. So it is not an exact science and all we can do is try to improve performance by eliminating any changes that are not necessary to get consistency.

J E CUSTOM
 
You need to do your own testing here. The advertised information is only so good. Powders act differently depending on the cartridge they are burned in. I have seen very contradicting data with the same powder in different cartridges. A good example is when I was working up loads for 2 rifles at the same time, one was running H1000 the other RL33. Conventional wisdom would say H1000 would be more stable. Rl33 blew it out of the water for day to day velocity stability. Like most things, believe little of what you read, you have to do it yourself.
 
Hello there! Dumb question I am sure but has anyone ever found published temperature sensitivity factors for varying powders? Right now I use IMR powders, guess just what I was taught with and it stuck. Would love to try some H1000 if I could ever get hands on it..... Have used the IMR's in all different calibers but want to get a load cranked up for my 7STW using 160gn accubond sand federal 215. Any info would be great.
 
Shooting in mid 90s to 100s during the summer I was getting some insane speed with a 180 berger and rl26 in A 7wsm. That same load in the winter was nearly 100 FPS slower. I couldn't believe how much it lost. Since then I have gone to rl23 and while it's not as fast in the summer, it's faster in the winter and incredibly temp stable. So yes it makes a huge difference. 100 FPS at 1k yards is 16" with my load. That's a complete miss on a white tail.
 
Here is some info. I make no claims as to accuracy. But the ones I have cross reference have been pretty close.
 

Attachments

  • 72-F33053-F125-4-CD9-92-C2-ED63062-E63-EA.jpg
    72-F33053-F125-4-CD9-92-C2-ED63062-E63-EA.jpg
    55.2 KB · Views: 331
Powder temperature stability is not a marketing gimmick its a factor of the chemical composition of each propellant. Some are better than others. Notably varget and H4350 are very stable through normal temperature ranges. With the interest in long range shooting where velocity spread does matter powder makers began using this in their marketing pitch. Alliant even came out with r23,26 which are new formulas to reduce the sensitivity normally seen in their reloader powders. Granted the average joe shooting critters inside 200 yds will not usually have issues even with the more intolerant powders. long range shooters and competitors will. Hence the popularity of varget in competition circles. As others have mentioned in can be a safety issue if you do your load development in cold weather.
 
In addition to the temp chart posted by redneckdan there is some excellent info right on the Hodgdon site about their Extreme Powders. Anyone that doesn't think Temp Stable is a Thang, have a look at the 10,000 CUP swing on Vint 550 from 70 degress to 125. From safe load to near being a bomb just from temp swing. Scroll down to see the comparison tables on the tested powders at different temperatures.

https://www.hodgdon.com/wp-content/u...ensitivity.pdf
 
Top