I've probably posted it 100 times you (I revised this section to keep from getting a timeout.)
BUT, since I wouldn't expect anyone to read each and every post on this forum, I'll go ahead and enlighten YOU.
I prefer 6mm bullets. I primarily shoot a bolt action 6mm WOA. It works very well, but I occasionally have to shoot a coyote twice. I have considered moving to 6x47 Lapua, but I think that some will require a follow up regardless, because of shot placement.... Now, that's not to say that my team can't shoot. It's due largely to the fact that we call in a lot of multiples, and often the last ones to bite the dust are the fastest and the farthest. As you (might) can imagine, they're a little hard to hit in the vitals.
My longest running partner shoots a 243 with 70 grain NBTs, and the combination kills them very well.
There will, of course, always be room in the truck for a 22-250, a Swift or even a 17 Remington, as all of these have a lot more (than a 223) of what kills coyotes better than anything -velocity.
More speed, more lead or at best a combination of both. That's what knocks them flat.
You can call me all the sarcastic names you wish, but the truth is my team knows where it stands around here. We aren't the best, but we're close, and I think that if we continue working really hard at it we will get there. We don't have to look for coyotes, so we've got that going for us anyway....