Originally Posted by blacklab
I think its easier to just shoot the gun at your prefered ranges
I wouldn't say it's easier.. usually more accurate yes.
But ballistics calculations can be very handy for 'what if' scenarios.. like.. How much advantage on longer targets would I get if I put higher mounts on?.. Yeah you could buy some higher mounts, fit them and shoot at bits of paper, but doing the calculation first is a lot cheaper and so much less hassle.
Then you've got cases such as... where do I aim for a 50 yard target at an incline of 35 degrees?.. Not so easy to set out a bit of paper for that.