air tempreture and bullet accuracy

[tony2]

i would like to know if air tempreture effects bullet accuracy only i zeroed my .22 rf for 50 yds and could get a grouping smaller than the size of a 2p piece but i have noticed that on days were the air tempreture has dropped the groupig gets bigger . i have checked the scope and mounts and they seem ok. the bullets i use are eley hp subs .

regards tony

[Oly]

It does have an effect as air density also changes...same as shooting at higher and lower altitudes. Not sure if you'll see that much of a difference with a rimfire, and without a match grade rifle too.

 

Maybe it's just that you're not as good a shot in the cold!

[Harnser]

Baromatic pressure can make a big difference in point of impact from day to day . More noticable on the longer ranges .

Harnser .

Edited October 4, 2008 by Harnser

[seisobs]

I can't get a decent grouping with eley's, maybe that's the problem, try winchester subs and see if your grouping improves.

[Baldrick]

Neither temperature nor pressure changes make a difference where a rimfire is concerned. It's something to be considered if you are shooting fullbore, and something that has a pronounced effect on artillery and naval gun trajectories.

 

In a little rimfire though, it's more likely to be your own reaction to the climate around you. I was trying to re-zero a rifle early this morning before the wind picked up, and I had to give up because of the shivering/numb trigger finger. The groups were all over the place. Pretty silly, in retrospect.

 

Stick with the Eleys. They're so much more consistent than Winchesters in my CZ and Anschutz.

[MC]

The biggest difference will be the effects on the burn rate of the powder when it is hot or cold.

 

When target shooting with a fullbore rifle the round is not chambered until seconds beofre you are ready to fire. This way it is not sitting in the chamber heating up and altering the ballistics of the round.