It's my personal belief that cal. is not as important as being competent with what hand gun you use,deer are not that hard to kill shot placement and
the willingness to let them walk if the right shot is not presented is key.
for me I hunt heavy cover (think bow hunting).30 yds and in.I'll use my s&w 586 4" or my 5'' 1911 Springfield.beyond this a 45 lc.or 44. If there out past 50 I use the ever preasent long gun,Use what you shoot the best.