I think the people who do it well might just be naturals ... like how we threw footballs at receivers when we were kids ...
But there is some science to it ... and though there are some variables ... roughly speaking ...
2 mph = 1.25 mils
so
4 mph = 2.5 mils
8 mph = 5 mils
16 mph = 10 mils
24 mph = 15 mils
Now these mph are "crossing" speeds i.e. the rate at which the critter is moving in terms of 90 degrees across your front. So if a critter is running 24 mph directly across your front hold 15 mils ...
If a critter is running 24 mph at 45 degree angle across your front hold 7.5 mils ...
So est. the crossing speed and hold accordingly.
Since I am not one of the "naturals" ... I really just think in terms of 5, 10, 15 mils for holding ... and this goes for hogs and yotes ... yotes might be a little faster in theory, but generally most of these critters are not crossing at 90 degrees to our front at their theoretical maximum speed.
So if the 2nd shot on a critter or group and the critter is first accelerating, then 5 mils ... next shot (on same or different critter of same group) 10 mils ... then 15 mils ... unless crossing significantly less than 90 degrees. I've had them run straight at me and straight away and in all other directions, not that they know where I am (I shoot suppressed), they are just running from the loudest sound they hear which is the supersonic crack of the bullet that hit their buddy or missed them (unless I am within 50yds, in which case, they usually hear the muzzle blast also).
At one ranch I go to, they have a mover stage in their match, but the targets are only moving 5 mph ... so about 3 mils works ... and you can predict it ...
So not that easy to setup a practice with 25 mphs runners ... I thought about doing it with a drone target tow, but it takes 2 people, and 97% of the time I only have 1 people, so I have to practice on the critters.
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Maybe one of the "Naturals" will weigh in on how they do it !!