Does cold weather affect ammunition?

[USAN]

Does cold weather affect ammunition?

https://www.facebook.com/video.php?v=1269783173110562

 

[MMAL]

Thanks for posting but I did not learn a thing from this video. How did the norma ammo do? what was the velocity change, if any, at the temp tested. What was the change in impact point? I know it might not apply to us specifically but the results would be informative.

 

[Dr Ray]

I believe cold affects the bullet when fired. But, the cold applies to the cartridge and temperature of the powder and not the air temperature.
Some powders are affected more than others. Australian powders often sold in USA as H..,,
Are not apparently as they are designed for the heat.
I believe that any effect would be very minimal in any case at normal hunting ranges.
Hope that helps.

 

[aleli]

We do a lot of winter hunting in Sweden and it is well known that when you need a lot of accuracy (e.g. when hunting capercaillie that is a small target often shot at 100-250 yards) then you should develop "winter loads".

The point of impact changes between 85 F to -20 F....

 

[CAustin]

Interesting

 

[GuttormG]

Rule of thumb; velocity changes 1 m/s per degree change of temperature.
Tested this this winter, shooting over chrono every time at the range; rule is quite close to spot-on. Probably not good enough for really long range sniping kind of stuff; plenty good enough for the rest of us.

For the non-metric ones; 1/ms is 3.28fps.

 

[lcq]

https://www.hodgdon.com/extreme-rifle-powders/ you will notice this is between 0-125F. That is a huge variance. Manufacturers load for safety and consistency so under normal hunting conditions I would hazard a guess that the inch difference in point of impact that may occur will not amount to the proverbial hill of beans

 

[gillettehunter]

Some powders are relatively temperature stable. H-1000 is a good example of that. Some such as RL-26 appear to drop in velocity about 1 FPS per 1 to 1.5 degrees Fahrenheit drop in temperature. If you are zeroed at 100 yds and hunting under 200 then this is not going to make any real world difference. A temp swing of 70 degrees is going to make perhaps 50 FPS difference in RL-26. Some powders may be a bit more. It would be somewhat unusual to see 100 FPS difference. At under 250 yds that is really not going to make any real difference.
If you are a long range target shooter at say 1000 yds then it can make a significant difference. It would then need to factored into your drop data to maintain accuracy. 50 FPS will make a difference there. Small targets, such as prairie dogs at 300 yds and further you may need to take that into account depending on your powder. For 95% of us its not enough of a difference to matter. The other 5% of us are generally aware and take it into account depending on our powder. Bruce

 

[Longwalker]

I find that all the other logistics related to hunting in very cold temperatures are more important to me. I'm pretty certain that ammunition does slow down in temperatures much colder than -10°C or so, but when it's -35 there are so many other factors that affect shooting like frozen fingers, frosted optics, very thick clothing, oil in the firing mechanism freezing and sticking, etc. That I tend to get close or pass on the shot. Usually if it's colder than -30 any more I stay home.

So a little less velocity might be important, but is not the most important.