ORIGINAL: wis_rifle_hunter
the .243 is the smallest i would go. i would never use anything smaller than that on a deer. i use a .243 right now and it barely knocks deer over so i wouldnt use anything smaller
W/ all due respect,there is no such thing as knock over or knock down power. A bullet, no matter how big ,cannnot push a deer back or to the ground, although it may appear that way somtimes. My 1st gun kill was a very small fawn, at point blank range, w/ a 30-06 180 gr, a legit 200yd elk gun, blew the things shoulder almost clean off w/ a chest shot. Tough LIL sob ran 50 yds, on what I dont know. Since then, Ive used , 12 and 20ga slugs, 308, 7mag, 44mag and muzzleloaders ,never have I knocked a deer over. Most run a short distance and some simply drop from a severed spinal cord or broken scapulas.
I have never done it ,but within 50yds ,I would have no problem taking a headshot at a calm deer,w/ any legal cal. Some guys think thats too risky, but I can hit a soft ball at 50 yds w/ my 223 more consistantly ,than a paper plate at 150 yds w/ my 7-08. Thing about those puny pills, they tend to go right where you want every time. Several guys I know, kill some pretty good bucks every year w/ single shot 22 hornets, even w/ rib and shoulder shots.