which is about 78 Square inches. 20" disk has 314 square inch target. 4x as big a mark. Once you fire a single shot, the only fully exposed mark you will get, that's holding STILL, is a head on prone man. If you have a fully exposed, stationary torso as a mark, in daylight, it's cause he's unaware of your presence. So you dont HAVE to shoot him. You just WANT to. Big difference. If he's unaware of you, you can get CLOSER, so why risk the miss, hmm? Misses at 500 yds are very commonplace. that's 1500 ft, and at least half a second of bullet flight. A man can cough or sneeze, moving his torso, in 1/4 second, or take a step in .5 second, and half a step is enough to make you miss.