Good advice from all. Like Dee, I choose the M4 shooting 55gr Sierra GameKings. The beast in my avatar was taken with this rifle. He was quartered away from me and my first shot was a bit low, but still got his neck. He ran about 50 yards and fell down. I promptly put one through his lungs and one more in his head as I walked up. Meanest hog I've killed and still put him on the ground with a badly placed .223. So any of the calibers you listed will work. Two things: 1st, terrain; if it's open, .250; if it's brushy 30-30; if both, AR. 2nd, pick the one you are most comfortable with.
My pattern now (because I hunt by myself often) is to either carry a semi-auto or if carry a bolt or single I will carry a pistol .40 or larger as well. My Glock 22 or my 1911 are usually what I have. . . just in case. I've only had one pig out of several hundred charge me, but it reminded me of the possibility and the need for a back-up.
Have fun and good hunting!