RE: 3 blade mechanical broadhead
As stated before, it depends on your setup. My KE is 67. I have shot Rocket 75 grain Miniblasters completely thru elk, antelope and Javelina, all dying within sight. Last year I had a 100 grain Snyper completely pass thru a bear. The bloodtrail was a good 8 inches wide The Snyper is a great head for lower KE setups because it doesn' t use up the energy to open the blades like so many other heads do. But, it isn' t a 3 blade head.
CBM, why would anyone want to use expandables at lower poundages? Because they do devastating damage like no fixed head is capable of.