How much can temperature affect POI?

[tlk]

At 100 yards? By temperature I mean outside temp, not barrel temp.

[Michael Eichele]

The density of the air due to temprature changes cause so little effect on POI I doubt one could accurately measure it. Changes in lighting conditions will cause WAY more POI differences at 100 yards then temprature ever will. Even out to 300 yards where I keep my rifles zeroed, I have never detected a POI change in different temps. Lighting yes, temps no.

As you probably know, when you increase the distance, that rule is out.

[BENNYBOOBOO]

I've asked around about this before, but nobody seemed to know a reasonable answer to WHY lighting causes a change in poi. Any suggestions? Also, HOW does lighting change poi?

EH

[Michael Eichele]

It isnt that the lighting in and of itself changes the POI, rather it changes the way YOU perceive the target.

[LRSickle]

That's the first thing I wondered too. I work with some guys that shoot their old military rifles in some military fun shoots and they say the same thing. They say the direction from which the sun is shining makes a difference. I'm assuming it has to do with how the front sight is lit up and may appear to be to the right/left of where it really is. Not sure, but that's my guess. I also wonder how it could effect your aim with a scope.
Can anybody shed some light on that?

[LRSickle]

That was quick. By the time I posted my question M E beat me to the post. Thanks for the reply M E.

[.280fan]

hmmmmm.....Seems curious to say that temp would not affect POI. At 100 yards, maybe it wouldn't affect POI much, but at longer ranges I would think that temperature does have an affect. Michael, I have your ballistic program and one of the set-up criteria is temperature. Sure enough, if you put in a set of data at one temp, then change it to another (generally an large change 30 to 70 degrees), the moa adjustment does change at longer ranges.