I like your sig line�..
Black dogs bark at night�.
ingwe;
Good evening to you sir, I hope this finds you folks well.
I recall exchanging some correspondence with MacKay about his sig line when I first started showing up in these parts. Somehow I recall the other part of the message to be something about John having a long mustache.....
We've got a neighbor who is a retired Vancouver PD constable that takes in all manner of dogs now. He's stone deaf so it doesn't bother him that most of his dogs bark all night - only some of them being black.
To the OP's question, while I really should have bought a .223 years and years ago, because of my relatively new relationship with the cartridge I can't say for sure it's the "most useful" quite yet. It does appear though that a decent .223 would get a whole lot of use at this point.
Based upon what we have played with over the years a fair amount, I'd have to agree with MacKay and the posters who've voted for the .308.
That said, there's no flies on a 7-08 either and our journey with the .250AI has been a smooth one for sure too.
Anyway ingwe, all the best to you folks and good luck on your hunts this fall as well.
Dwayne