Cold weather and accuracy

[datatools]

First powder I ever tried in my .308 was IMR3031. Worked great all summer long. Then winter hit and I had the same problem as you.

Now I only use Varget, because it gives consistent velocities from winter to summer to winter. Only very minor tweaking is ever needed if you want exactly the same muzzle velocities.

Hmmm, I dont have any Varget on hand but I have some RE15 and IMR4064. I'm going to try some groups with these in the cold temps and see what happens. The thing that bothers me about this is that the rifle and ammo dont really have ANY time to cool off before I fire the group. I take them right out of the warm vehicle to the bench and fire a 5 shot string back to back shots.

 

[warrenb]

If velocity is changing, so is barrel time, and your load is moving off of your accuracy node as temperature changes...

Using the Extreme powders and loading to an OCW node helps mitigate this.

.

Thats excellent information!

My apologise if I am asking you to repeat what you may have posted before but do you have any similar graphs for Varget and other extreme powders.

 

[kombayotch]

I need to put the info on a website... I probably get asked for it 2 or 3 times a week in PMs...

 

[Nathan231]

Hmmm. That chart is interesting. I suppose if you wanted to go extreme you could say that under extreme cold and extreme heat your barrel has contracted or expanded which would affect accuracy. Interesting, never though of it like that.