Been shooting "goats" for 30 years. Guess I am lucky to live right in the middle of Wyoming. I have shot them with everything from a .243 to .375. The .270 works great. As will a .243, 6mm .257 Roberts and so on.
Now a days I hunt them with a bow. Still I have my favorite antelope rifle on stand by. A custom Sako in .250 Ackley Improved.