While I own 3 223s, (sporter, heavy barrel and AR), as well as a 243,7-08, 308 and have taken deer with all three, my main deer rifles are chambered for pretty old cartridges. A pair of 250-3000, .257 Roberts and a seldom used these days 270. A Ruger Tanger M77 .250-3000 took my buck this year, gross scored 161 and big enough I didn't even try to load him. Just went home for the 4 wheeler and a chain to drag him in.
My most fired rifle is probably my '94 Marlin 25-20, it's shot thousands of rounds with various cast bullets on steel gongs and small game.
My 30-30 was a 336 Marlin that has now been bored out to 38-55 and gets a steady diet of 250 grain cast bullets. Took a doe during early doe season, but mostly it gets used on my backyard gongs.
Never got into the magnum craze, just never felt I need more that what I had.