If you do the math again, and then look at Brister's pix, it's easy to see that a 12 foot long shotstring fired at a 50 yard 50MPH crossing duck takes about .02 second to pass the target - and the target moves a foot and a half in this time. Your neat little 30 inch 70% circle on the pattern board turns into a four foot long patchy swath from the frame of reference of the target.
There isn't anything near a 70% pattern presented to a long distance fast crossing target. Half the pattern will pass ahead or behind.
Can a good shooter hit it? Sure, he can hit it. I've shot with plenty of guys who I wouldn't bet against hitting a 50 yard 90 degree deflection target. But... can you KILL it? Different story.
