It's actually possible to beat Russell without weapons or cheats, but it takes patience and timing.
I agree. When Russell starts to do a bull motion, run quickly to the left or right. Keep moving in one direction as he is charging at you. Keep your distance so he has less chance of hitting you. Blah blah blah, he'll charge at the wall, get dizzy, and then you beat death into him.
The difficult part is the second half of the fight, which is when his life bar is about halfway down. He'll pause, yell loudly, and then start chasing you. If he catches you, he'll hold you in a lock (hard as shit to wrestle yourself out of on the PS2 version) that can take quite a bit of health from Jimmy. Pretty much the only way I've found to avoid this is to bring Jimmy to the edge of the circle and run all the way around as Russell attempts to catch you. He'll eventually get tired, and then you can beat him.