I would just use a standard soft point 55 grainer. Lions are very easy to kill. Whether called or treed, lions are usually a short range affair. 22 LRs and 17 HMRs kill they very well, as does most anything. If you do use a lesser expanding bullet, take advice from above and wait a while before finding him. I've killed a fair number of cats, but the most trouble I have seen is from stout buulets blowing right through the animal and not doing a lot of damage. FMJs out of a 38 special have caused 2 expensive vet bills in my presence.
