I have done quate a bit of hunting with mine!! I have a factory bbl in 357 maxi.
I shot a couple deer with the 180 Hornady SSP bullit. At top velocities it is too lightly constructed for good penetration on Mr. Whitetail so on your slightly larger Mules its not the best choice. I am now using the SPEER 180 designed for the 35 Rem. It works GREAT!!! Better SD than the pistol 180's. The Hornady XTP 180 shows promice but hornady them selves rates it as working velocities lower than what you can/ will be able to get from the 21" BBL handi!!
Remember most if not all data out there is for PISTOL barrrels!! I was able to get almost 2300FPS from my top loads. 1680 is the magic powder for my handi!!
here is a pic of the last two deer I shot with my handi 357 maxi. Shotgun I am holding is my pops, I had already made a trip back to jeep with all extra gear and left him with deer. So thats all we had for the pic. Thats also why I have no orange on.
Good luck,
CW