Temperature

[dcederberg]

How much does temperature effect bullet drop? I sighted my Ultra Mag in last fall in say 40 degree temps and all of my dope was spot on. Now its 75 degrees and everything seems pretty high. I had some gun smithing done on my Sendero, New trigger, Sako extractor and action and barrel trued up. Sighted back in dead on at 100 yards but now my dope seems to be high. Could this be just Temp??

Thanks, Ceder

 

[dragman]

Depends on your component list and your program. at say 1000 yards with that kind of difference in temp I would have to take out about 1.25 MOA

 

[dcederberg]

Thanks for the feed back, it just seems like my dope should be the same even after the gun was worked on. The only real difference is the outside temp. Looks like another good selling point for a G7 range finder.

 

[dragman]

Yep it's all about temp, pressure and air density

 

[Tumbleweed]

Yes, air temperature will affect bullet flight/drop. Don't forget about your internal ballistics. Part of this could be your powder reacting to the outside temperature causing a higher velocity, hence the higher point of impact. Some powders are more sensitive than others to temperature swings. You'll just have to account for it in your charts or ballistics program.

 

[dcederberg]

I am shooting Retumbo, I dont know how temp sensitive that powder is. I think it is supposed to be one of the better ones for large calibers. I think bottom line is I am going to put it on paper from 100 to 1000 and adjust from there. Does burn up some ammo but it sure is fun!