How far out can you get before you have to worry about atmospheric conditions, etc

[Partagas]

Does it depend on caliber, bc, and velocity or is it kind of a constant? I am wondering if you don't change elevations to much from where you regularly shoot at what all you have to worry about. And how much elevation change is too much before your poi changes?
Thanks

[Charles A]

It depends on all of the things you posted, however, the faster, higher BC bullets extend the range. With the 308win somewhere around 500yds or so, the 300winmag extend that out too about 700yds, and the 300RUM about 900 yards. Of course this also depends on the size/shape of you target. A human target has a different set of varibles, than a deer. The only way you'll know what YOUR rifle does is too shoot it and log it, in different weather conditions. [img]images/icons/smile.gif[/img]

[cdmorten]

What Charles said. I've finally started logging my shooting, keeping track of temp, wind, POI. I should probably start keeping track of barametric pressure as well. I don't have a good grasp on that factor. I'd like to know more.

[Hired Gun]

A balistic program like Barnes's balistic program will give you the info. If you give me your caliber, bullet weight, muzzel velocity and zero range. Then the different altitudes I could give you an idea how much it changes your down range trajectory.

I just played around with one of my loads and at 975 yards a change from sea level at 60 degrees to 15,000 feet and 10 degrees changed the drop from 163.45" to 123.52" Thats a little over 3 feet difference. That is a pretty extreme change. I really doubt you ever hunt or shoot high enough to ever have to adjust for it. A strictly barometric change would have an even less affect. A 5000 foot change in elevation changed impact by 17" at 975 yards.

So, I guess if you're really stretching it out there then you may have to adjust a bit for it. Shoot me your info for your situation and I will run it across my program.