The chuck hawk site has some good info. but there are a few free online ballistic software sites you can go to.
You don't have to download anything just use their site.
Go to
www.biggameinfo.com and click on external ballistic program ,then just plug in your info .
With a little research to find your bullets actual -bc- -then plug in your elevation , velocity etc..
Although the bottom line is you still need to shoot ' your ' gun at these ranges.Don't shoot in extreme hot or cold temperatures b/c you'll get higher velocity in hot weather and lower in cold.
Since this info is on a big game site -i disagree w/ using it on predator/varmints b/c your target is MUCH smaller.Look at the mid-range trajectory -you'll see that you can easily overshoot and animal at 150yds..
Personnaly for a predator calling rifle i don't like the mid range rise to be more than 1.5" so a 22-250 hitting dead on at 200yds is perfect to me..
Get out and shoot out to 300-400yds --a lot of fun and easier than you think to make good hits...