I've run the 195 gr Powerbelts with 100 gr 777 through my 45 cal CVA into a couple whitetails and not had the best results either.
As a matter of fact on NYD 2015 I put one into the neck of a fawn at about 100 yds and recovered it.
Today a buddy put a 250 gr Hornady SST Sabot from his 50 cal TC pushed by 100 gr buckhorn 209 straight into the brisket and through the heart at 50 yds:
It penetrated deeply & retained a lot (haven't weighed it yet) of weight despite the high impact velocity.
I'll be trying those in my .45 and in my .50 the Barnes Spitfire TMZ.