Temperature change affects rifle zero how?
quote:Originally posted by cubslover
Nononsense, Perry, HeavyIron, help me out.
The two firearms of importance are 50cal CVA Optima ML, and Marlin 1894 in 44mag.
If I sight these guns in now, in the 80-90 degree heat, will the POI be severely different when checking my zeros in November just before deer season? Or should I just wait to sight them in until the weather changes?
It's pushing the mid 90's here now, but by Firearm season, it will be down with highs in the low-mid 40's, then highs in the 20's for Black Powder season.
quote:Originally posted by Herschel
It does make a difference at long range. From my hipower shooting days I believe the rule of thumb was 10 degree change in temperature would change the impact 1 minute at 600 yards. This was with .30-'06 and 7.62 mm nato. Of course the change would not be that exact amount but that was the estimate of change.
quote:Originally posted by cubslover
Thanks for the reply Herschel. My longest shots will be about 125yds with the ML and 80-100 with the 1894. Around here you really don't need to take shots longer than that.
So assuming Herschel is correct, how does the temperature change affect the zero? Randomly? Warmer barrel = higher POI? Why not left to right?
Nononsense, Perry, HeavyIron, help me out.
The two firearms of importance are 50cal CVA Optima ML, and Marlin 1894 in 44mag.
If I sight these guns in now, in the 80-90 degree heat, will the POI be severely different when checking my zeros in November just before deer season? Or should I just wait to sight them in until the weather changes?
It's pushing the mid 90's here now, but by Firearm season, it will be down with highs in the low-mid 40's, then highs in the 20's for Black Powder season.
quote:Originally posted by Herschel
It does make a difference at long range. From my hipower shooting days I believe the rule of thumb was 10 degree change in temperature would change the impact 1 minute at 600 yards. This was with .30-'06 and 7.62 mm nato. Of course the change would not be that exact amount but that was the estimate of change.
quote:Originally posted by cubslover
Thanks for the reply Herschel. My longest shots will be about 125yds with the ML and 80-100 with the 1894. Around here you really don't need to take shots longer than that.
So assuming Herschel is correct, how does the temperature change affect the zero? Randomly? Warmer barrel = higher POI? Why not left to right?
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Air density (altitude) Humidity-
Powder thats temperature sensitive-
Anything in the air that can effect the resistance of the flight of a bullet can and will. It may be small, but at very long ranges anything can happen.
No expert- But I do know humid days vs dry cold days my .308 will shoot different at 400 yrds at sea level. Not much, but enough to see it on paper.
Edit: Wanted to add, I learned my 22-250 using H380 on a hot day Vs. using Varget on a hot day in the same area makes a huge difference. Why? H380 is not as stable in extreme temps as Varget. But thats my own opinion and not scientific fact.0 -
Higher temps and humidity levels will increase pressures, resulting in higher velocities...you might shoot a little high in the summer if your rifle was zeroed in the winter. You also have to keep an eye on your pressures if you are pushing max loads. 0 -
Which way the sun is shining on the iron sites sure does affect things! 0 -
quote:Originally posted by ECC
Higher temps and humidity levels will increase pressures, resulting in higher velocities...you might shoot a little high in the summer if your rifle was zeroed in the winter. You also have to keep an eye on your pressures if you are pushing max loads.
Bingo!
Extreamly simple physics!0 -
Here is a site I use to check drift and temp changes. It will make a difference on temp. Though you will never know at under 200yds. It is plug and play so you can enter lots of varables.
http://www.eskimo.com/~jbm/ballistics/traj_basic/traj_basic.html0
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