I second Toddc for the Burris Eliminator III.
Burris has a "ballistic library" for most commercial cartridges so you find your cartridge and choose that "trajectory group" and input it into the scope. You need to enter the bullet BC and muzzle velocity as well.
Eliminator III software, laser and angle sensor account for the following:
2. lighted dot for correct range with your cartridge
3. angle compensation automatically included in firing solution
4. 10 mph. "wind dot" holds in a "Christmas tree" reticle
5. trajectory lighted hold dot accurate at any magnification
BUT... I prefer the advice of s.joden for the Leica HD-B 10x 42 binoculars. With these binoculars you enter your rifle's EXACT ballistics with a given cartridge, even a handload, on a micro SC card on your computer at Leica's ballistic site, insert it into the binoculars and the binoculars have sensors for:
1. temperature
2. angle up or down
3. altitude density
4. distance (laser rangefinder)
Plus excellent glass.
So you can use these binoculars with any rifle with MOA or mil hash mark reticles and be very close to a perfect hold over (or under) and "all" you need to do is dope the wind correctly. You can choose MOA or mil hold and yards or meters for distance.
Let's face it, for western hunting you absolutely need binoculars so why not get these damned expensive Leica HD-B binocs (buy once cry once) and have your hold instantly?
I use the lesser Bushnell 1 Mile LRF binoculars and like them but "lust after" the Leicas like the gearaholic that I am.
Eric B.
Eric