Since your OP stops at elk and Kudu:
.243 Win.
.30-06
Those would be my picks as well, though I'm sure that lying little pansy from puzzyville AK. would need a 243 AI and .30-06 AI to accomplish anything. That's providing the stupid little schmuck could get Jack Belk or some other knowledgeable smith to build the rifles for his sorry little self of course.