A summary:
I would say, Black hills 77gr molly coated hollow points.
*Note: Disputed/questionable choice.
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There are a few suitable soft points, if you drop down to 55gr there are a gazillion choices. Stay away from ballistic tip and HP rounds, maybe do a water jug test to make sure the round won't fragment like a varmint round.
I've got boxes of Barnaul steel cased 62gr soft points, in a pinch I'd take a deer with one. If you can take a good shot with it expansion won't matter too much, just stay away from varmint rounds, unless you love eating coagulated meat with bits of metal in it.
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By all accounts the Barns TSX is THE bullet to use for hunting medium game with a .223 followed closely by Winchesters 64grn power point. I don't have any firsthand experience using this cartridge on deer....YET. But I'm likely to remedy that come November
By all means read some of the reviews written for the ammo listed in the below links
http://www.midwayusa.com/eproductpag...348&t=11082005
http://www.midwayusa.com/eproductpag...682&t=11082005
http://www.midwayusa.com/eproductpag...153&t=11082005
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I'm not a hunter, but people who hunted deer with .223 have said that the 60 nosler partition seems to work well.