I agree that a bigger chambering with more energy has a better chance of knocking a deer down than a small cal with alot less energy and velocity. And it comes in handy when the deer is quartering towards and you need to bust the shoulder. I like to use an adequete cartridge, such as 30-06, 270, etc. I wont deer hunt with a 223
I know thats its said that knockdown is a myth, but to me, id think a 300 win mag would do it before a 243, so theres gotta be something to it. I mean, theres really no evidence either way.