Temperature affect Accuracy/Consistency ?

[3dmark]

Curious how much accuracy would be affected if any when its say -10c compared to say 10c.

Shoud a five shot group be as tight at -10c vs +10c ?


I shot today and it was -10c and my groups really opened up from the other day when it was +5C outside. Is this normal.


Thanks

 

[22lr]

keep your ammo inside your parka. Ammo temperature often affect powder burn rate and ignition quality of primers. If your hammer spring is already on a weak side shots at colder temperature will be less consistent, they will even sound differently fron shot to shot. On top of that there is also barrel harmonics that are very dependant on a temperature.

 

[Ruffed Grouse]

I don't know that there are any rules about temperatures for optimum accuracy. But it is true that any given gun or load may react differently to different temperatures.

For example, I have a Ruger #1 that will shoot sub-MOA as long as it is not hot and humid out. In the case of this particular gun it is not surprising that there is an effect of humidity because the stock touches the barrel, and changes in the wood could then have an effect. But I don't know that you could predict before hand what temperature or humidity would be best for that gun.

The other way that temperature could affect accuracy is through velocity. At lower temperature, powders burn differently, and generally lower velocities result. So the exact moment that the bullet exits the barrel will change, and depending on how your particular barrel on your particular gun vibrates during a shot, this could change accuracy, but not necessarily in a way that you could predict a priori.

RG

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[taffman]

I am really wondering about heavy barrels and -30 days. I don't think all the powder even burned off in the barrel. The gun was absolutely filthy and a 1/2 inch shooter produced 5 shot groups when it was that cold.

Put the heavy barreled rimfires away and brought out the pencil thin barreled rem 700 mountain rifle in a .270 and it shot like a dream.