What they said about the 45ACP. It is a great man stopper, but not nearly enough for deer. There are some great deer hunting HG's out there, in both double and single action revolvers. I would suggest the minimum round be .41 Rem Mag and from there the choices are almost mind boogling, like 44 Rem Mag,45 Long Colt, 480 Ruger, 460 S&W, 500S&W, and my personal favorite the 445Super Mag.
I would recommend a minimum barrel length of 6", with 8.5-10" being the optimum. High viz sights are a must if you are going to use iron/open sights, especially in low light. If shots are going to be 50yds and less iron/open sights will do fine and a holographic sight like EO Tech, Red Dot, or Aim Point type optics will also do very nicely. If shots are goignto be 50-100yds you may want to consider a low power fixed scope like a fixed 2x.
There are some good revolvers out the these days, with Ruger and S&W at the top of the list. For the money it would be real hard to beat Ruger, with there Blackhawk/Super Blackhawk and Redhawk/Super Redhawk line. MyRuger deer hunting HG is an old model Blackhawk 45LC with a 6.5" barrel. S&W have some very fine models as well and I really like the Model 657. But my absolute favorite hunting HG is my Dan Wesson .445 Super Mag. I have 6", 8", and 10" barrels for it, but use the 10" 99% of the time. I have a 3MOA AimPoint on it and it is scary accurate out to 100yds. I shoot 32gr ofH110 and a 240gr Hornady XTP at 1,742 FPS and deer and boar just can't stand it as it lays the smack down on them. I can also shoot 44 special and 44 Rem Mags out of it as well. I have never shot 44 specials in it, but do shoot 44 Mags in it from time to time. Dan Wesson is now owned by CZ and I hear good things about them.
http://www.cz-usa.com/product_detail.php?id=79
.44mag vs .45acp?
