I picked up a .243win specifically for antelope...

Have used a .270win for years.

Anything from .243-270 is ideal I think, they say the .25-06rem is the perfect goat gun, though I'm not certain what's the perfect goat gun, my guess might be the .243.

The .240wby might be perfect but the ammo is expensive and it's not very popular, a fast .243 would be awesome, ie 6mm-284, though again none are very popular.

The .257wby is one of WBY's most popular rounds, 3rd I believe behind the .30-378, then .300wby, so if I was going the route of the 270wby I think I'd strongly look at the .257wby. Although while you're looking at the .257/270 why not just a .270wsm, velocity plus a short action...though you really don't need anything in the power class of the .257wby or .270wsm to take an antelope even way out to 500+ yards.

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