Best ballistics calculator?

[RangerBrad]

Hey fellas, I have been using the G7 on line and like it however, I would like a calculator to take to the field. Can yal recommend a good one to me that is intuitive as I am somewhat technacilly challenged. I have an I phone so I would like one that I could either load the app or one that I could put on another device. Thank's, Brad

 

[Mike 338]

Shooter is great.

Shooter (Ballistics Calculator) for iPhone 3GS, iPhone 4, iPhone 4S, iPod touch (3rd generation), iPod touch (4th generation) and iPad on the iTunes App Store