Sorry to fall back off the posting wagon, personal health issues got in the way.
Cheaper than Dirt has an excellent post up at their blog regarding maximum point blank range and battlesight zero. If you’re one to not fiddle with your sights much, the information can be quite useful for squeezing maximum effectiveness out of your hunting or field defensive rifle.
Another place where ballistics calculators and knowledge of your particular firearm can be of use is with your handgun. What’s that you say? Handguns are only useful for close range defense? In an ideal world you would be correct, but conditions aren’t always ideal. During the Columbine Massacre the first two officers to arrive on scene were engaged at a range of around 70 yards by the teenaged butchers. Had the officers been practiced in shooting at long range with their service pistols there is a small chance the outcome would have been different.
Using ballistics charts and some experimentation you will find that if your handgun is accurate enough you can deliver effective fire at ranges up to at least 100 yards. With all but the poorest quality of handgun you should, with practice, be able to deliver suppressive fire at that range. A skill that could be useful if you are left with NO other options.