I am one of the few (kidding) who own an iPhone. I always make my phone work for me. If I'm at work I'm using maps, directions, VIN scanners etc. Never a dull moment. A couple of weeks ago I ran across a program: Ballistic Field Tactical Edition Ballistic: The Pro Ballistic Trajectory Computer for the iPhone, iPod Touch, and iPad Decided to play around with it and see how accurate it really was. Starters: Couple things to notice on the above image: 1. AR in .223 caliber 2. Round Muzzle velocity 3. 3" Sight height (from center of barrel to center of scope) 4. My sight in at 100 yards is 1.5" high (had to find my zero and adjust it until my 100 yards came out right) When all of that is punched in and you let the program calculate everything you end up with a ballistic graph like this one: (it's calculated for Remington PSP rounds and not that I will shoot out to 1000 yards.. I normally set them up for 500) So once you have your information input and its accurate you can set up a HUD where you just dial in your yards and it will tell you how much of a drop and what windage to set... can't seem to get mine to show up. Oh well. Check out the link above for more info. So. Anyone else use it?