The amount of folks with even "some" training on this are usually not within, let's say a 12" Mule deer vital zone once you start to close in on 300ish yards (yes the true "vital zone" is/can be larger). Shooting at rocks the size of an elk that stand still and stick out, with no pressure and no time limit, sure you'll get hits, maybe, with practice and a good known/reticle and gun/load. Or with somebody well trained with a good/known MIL reticle in a spotting scope is the real way to do this.You can with a mil reticle scope.
In my opinion (which doesn't even really matter haha) you have to be very high level and practice weekly, to be able to judge and then only use your reticle to come up with a range. Then you have to shoot into a vital zone in field conditions where elite guys who shoot in the mountains weekly are really only 1.75-2.5 MOA shooters as it is.
Say a guy and his rifle/scope setup is a 2 MOA "overall system" in the mountains under pressure (these are RARE despite what youtube tells you) and you've estimated through your reticle that a mule deer is 350 yards away. You already have 7" of "potential error" just in the shooter/gun, compounding with whatever error you've introduced with your "yardage" being slightly (or greatly) off. I guess what I'm saying is, it leads to a whole lot of misses in what I've seen.
I'm not at all saying this is "bad" to practice or put into use... But to say that average Joe is going to start using his MIL reticle in his rifle scope to come up with ranges and reliably kill? I'm sure you're already well aware that this is not realistic.