Cold weather powder/primer temp sensitivity testing results

[Walkalong]

The scene from the dumb and dumber movie where he licks the pole and it sticks? That really does work.

Tested out that theory when I was a kid, stuck my tongue to an ice tray straight out of the freezer. (For those who remember metal ice trays.

 

[GarrettJ]

Interesting.

Keep in mind, you can have other factors influence your results. The most obvious is the angle of the sun, relative to your chronograph. Other factors like differences in barometric pressure from one day to the next may have a small influence as well.

I did a mini version of your test several years ago, using H110 in .300 Whisper. To minimize these external influences, I put a metal mag of ammo in the oven and warmed it at 150 deg. The mag then went into an insulated lunchbox on the way to the range. A similar mag of ammo was left out in the cold.

I would have to dig for my notes, but I want to say the difference in average velocities was less than I had been led to believe with this powder.

 

[Stumper]

I wonder if the L'il Gun performance at low temps is due to high nitro-glycerin content? A similar issue has been documented with Blue Dot at very cold temps in metallic cartridges. One of the theories proposed was that frozen Nitro glycerin within the powder fractured from the primer explosion altering the burn rate.

 

[Toprudder]

I started a thread on Saturday with some chronograph testing comparing a few of my loads worked up in warm weather and shot in the cold. Well today I did some more extensive testing and I decided to roll the two threads into one.

Thank you very much for posting that. Shooting in those conditions, collecting all of the data, and reporting it here takes effort that I know myself and others appreciate.

I would not have expected Lil Gun to have a negative temperature coefficient. I also did not expect H110 to do as well as it did.

 

[Bbear]

Used to use Lil Gun in a Casull I had years back. Worked great for that round. I was surprised with the RL19 info. My experience from loading 25-06 with 110 gr Accubonds at 40 f was decent speed (around 2900 or so) and good accuracy. The problem came when I shot it in 100 + f temps. Bolt became hard to open and the rifle shot patterns instead of groups. All of my RL 19 is now fertilizing the garden.
Switched to 7977 and haven't had any problems with temp sensitivity.