Cold weather load development

[Klondiker]

I'm in the process of working up an 'accuracy' load for my .308 bolt. I've heard some powders may be more temperature sensitive than others, but aside from changes in point of impact, will the cold make a load more inaccurate (or more accurate) than it might be when it's +10 instead of -30?

FWIW I'm using IMR 4064.

On the bright side, at -30 I guess I won't have to wait long for the barrel to cool

Thanks for any input.

 

[manitou210]

4064 is not the best you might want to use varget or any of the Hodgden Extreem powders

 

[dead meat]

I just recently read about this subject just can`t remember where. Definitely some powders give reduced performance in the cold, kind of like my memory. Somebody will be along with the info.

 

[FTRRookie]

Try this other active thread:

http://http://www.canadiangunnutz.com/forum/showthread.php?t=696728

The gist of it is that at whatever temperature you find a load that works for your gun, you'll need to tweak the powder charge depending on temperature to stay at that MV. A powder like Varget will help minimize the amount of tweaking.

 

[DG Photography]

You can be lazy and hot box your ammo Cooler+hand warmers and temp gauge = poor mans ammo hotbox

 

[Klondiker]

Thanks for the input guys.

Seeing as I've built 80 rounds of varying charges, I don't really want to pull 'em and start over.

I'm thinking of trying the 'hotbox' method. You're not pulling my leg here are ya?

 

[Jordan Smith]

Warming up the ammo will help, but the temperature of the chamber and barrel, as well as the air, also makes a difference.

 

[caustic]

Warming up the ammo will help, but the temperature of the chamber and barrel, as well as the air, also makes a difference.

this ^^^

 

[dthunter]

I would make sure your ammo is at the ambient temp.
This way it will not be cooling off when shooting. If you want consistant results, just record the temp, and be sure to retest this load (if good) at a different temp.

I record my load velocities,SD,ES at 10C intervals.
This allows me to adjust my scope adjustments more consistantly at longer ranges (1000-1760).

It takes time, but keeping records will pay serious dividens!
There is nothing like a first round hit at over 1000!
Especially after a big weather change!

Record, read conditions, adjust,send,hit! GLORIOUS!!! Lol!

 

[Klondiker]

Thanks for the input guys!

I'm off tomorrow to give it a whirl. I've got the chrony packed up and I'll keep track of the data. When it warms up I hope to get out with the same loads and see how they differ. Now I'm really curious what the deviation might actually be.

Greg

 

[Camaro2010]

I would make sure your ammo is at the ambient temp.
This way it will not be cooling off when shooting. If you want consistant results, just record the temp, and be sure to retest this load (if good) at a different temp.

I record my load velocities,SD,ES at 10C intervals.
This allows me to adjust my scope adjustments more consistantly at longer ranges (1000-1760).

It takes time, but keeping records will pay serious dividens!
There is nothing like a first round hit at over 1000!
Especially after a big weather change!

Record, read conditions, adjust,send,hit! GLORIOUS!!! Lol!

I agree 100%! This removes any guessing in the future when you are trying to replicate your results.

 

[Tcon]

Thanks for the input guys!

I'm off tomorrow to give it a whirl. I've got the chrony packed up and I'll keep track of the data. When it warms up I hope to get out with the same loads and see how they differ. Now I'm really curious what the deviation might actually be.

Greg

Hope your chrony works, mine is the middle of the road offering from chrony and it stopped working in below zero temps.