If I haven't made the shot in practice, I don't try it at an animal.
If you've proven the distance you can make the shot and proven when you can't, your limit is a known.
Otherwise, why set an arbitrary limit?
The 300 yard limit is as far as I want to use an elevation turret and a plex reticle without any windage hold marks.The edge of the thick portion of the plex is 3 moa from center. I figure I can guess wind as far as 300 and not be off enough to miss a kill zone.