I'm mostly a 308 user on deer myself, but that doesn't make smaller cartridges less effective. For a long time I thought a 243 was light for my hunting purposes. I even missed out on a great deal on a special rifle because it was a 243 and at the time I didn't know better. Time passed, I collected a bunch of information by directly observing the results of others of my acquaintance, and so I started using a 243 myself. Having shot some game, including a rather large boar hog, with the 95 grain Ballistic tip I'm now quite satisfied with a 243 as a cartridge for my hunting purposes.
I think most consider 6mm the minimum, except the guys around here think it is to big.
There is, or was until Photobucket took a crap, a large reservoir of pictorial evidence on this site provided by actual users of the 223 on deer and pigs. For those who've tried it with appropriate projectiles it has been quite effective. Besides, I don't think the comments calling the 243 too big were serious, more likely being bait.
