Don’t know about your friends success rate with 223 Rem. I’m sure he’s killed deer with it. I don’t think it is a good one for deer out at 500 yds. Compared to other potent 224s like 22 Creedmoor, 22-6mm and 220 Swift, which really move 88 grain weights fast, the 223 doesn’t come close. Not saying it’s not a great cartridge, just saying it lacks a lot on deer size game at 500 yards. It would really struggle to get an 88 grain out at 2,500 fps, the others would be at velocity ranges of 3,200 fps-3,400 fps with an 88 grain bullet. This translates into 500 yard impact energy at about 650 ft-lbs for the 223 Rem, the others would be producing around 1,200 ft-lbs, or about double, quite a big difference using a .224 on deer at 500 yds.
