Question about temperature sensitivity - H4350, IMR 3031, and VV N550

[kentuckyMarksman]

Ok, so I don't get to go to the range very much, just once every few months, but I go every chance I get (young kids keep me busy).

I've got several load ladders all loaded up, and it looks like I can get to the range on Saturday for a bit. I have a 6.5 Creedmoor ladder with H4350 and 140gr ELD bullets, another 6.5 ladder with N550 and 123gr ELDs, and a 308 ladder for my M1A with IMR 3031 and 168gr SMK bullets. It will be about 25 degrees Fahrenheit Saturday.

I'm concerned about temperature sensitivity, and if I have loads that group really well on Saturday in 25 degree weather doing badly in warmer weather. Am I overthinking this? How much of an issue will thus realistically be? Should I just shoot factory ammo till it warm up?

 

[Holliday]

I put my ammo in a small cooler with bottles of hot water. I generally try to keep them 70° - 90 ° for testing. Make sure nothing leaks and gets the ammo wet.

 

[kentuckyMarksman]

Thanks. Things changed and I'll be going Sunday instead. Be in the low 40s then, so a bit better.

 

[Shootin Stuff]

Any of the rebranded ADI powders (Hogdon) are pretty good with temperature stability within a normal ranges. Some of the other brands speed up A LOT when it gets hot outside.

 

[Baron23]

Google is your friend ;-)

Powder Temp Stability — IMR Enduron vs. H4350 and Varget « Daily Bulletin

A couple seasons back, PrecisionRifleBlog.com (PRB) published a significant field test of powder temperature stability. The test was designed to quantify the temperature stability of Hodgdon H4350 and Varget powders compared to IMR’s Enduron line of powders, specifically IMR 4166 and 4451.

bulletin.accurateshooter.com

Not all the powders you were interested...but I just looked for H4350

Cheers

 

[RTH1800]

If loading near the top beware of going too hot in cool weather. Hot weather can push them over the top.
Also keep ammo out of direct sunlight in hot weather. It can get catastrophic fast.

 

[4O6shootist]

In my 6gt w/ 36.6gr H4350 25° is 2895fps and 90° is 2925. My rifle shoots the best at 2910 so in cool matches I run 36.7, July/Aug I run 36.5gr rest of year its 36.6, varget has show a lil more temp swing. Imr 4166 is very stable as is rl16. Believe I observed 15-18fps in 60° changes.