I have shot the 265 grain Hornady in an old Browning M92 and killed deer and antelope with them. I can't say how much they expand because I have never recovered one, but the exit holes were about 1" in diameter, so I have to assume they expand some.

I also killed a small bear with one out of a 7 1/2" Ruger Redhawk years ago, and dropped the bear with one shot.
I didn't recover that bullet either, but I have to believe they are expanding at least a little