My favorite shot on a deer is quartering towards me. I like to bust the facing shoulder, put it through the vitals, and preferably exit behind the off shoulder. Short of a spine or brain shot, this one has dropped more deer in their tracks than any other for me.
I use 158g Remington SPs between 1600-1700 fps out of my 1894C, and with this load you can easily bust a shoulder on entry, or on exiting, as well as tear up the vitals very nicely in the process up to 100 yards. With my Blackhawk, and a velocity around 1300-1400 fps it'll also work the same way up to at least 50-60 yards or so.
My bullet of choice before I switched to the Remington SPs was the 158g XTP-FPs. With a velocity in the same range, they also worked well, but the Remington SPs are slightly better in my opinion. I've busted both shoulders on a deer a few times using the XTP-FPs and I know beyond a doubt that the Remingtons will do even better.
The heavier bullets will definitely penetrate like crazy on a deer, but you don't have to use them for consistent results. I've tried them, but the 158g bullets consistantly do more damage to the vitals making a lot shorter tracking job(usually only a few yards) in the event that a deer does run before falling. The 357 bullets(even cast) don't have a huge frontal area to help in shock, or wound channels, so in my opinion you need at least some expansion to make sure the vitals are damaged enough for quick kills.
The 158g bullets won't penetrate as far as say a 170g-180g hard cast bullet, but they "will" make it to the rear of a deer on a straight on frontal shot, sometimes even exiting. They'll also tear up the vitals better which, if you do take a straight on frontal shot, you'll quickly find out is a good thing to have working for you. The vitals aren't easy to tear up at that angle, as the bullet tends to end up going more or less between the lungs, and if the heart, or arteries are missed, you'll be tracking a long time.
As far as pure penetration in any caliber using any bullet, it all depends on the impact velocity. I've even shot deer with the 125g Remington SPs, and had decent results, with full penetration after breaking the facing shoulders. I loaded them in 38 cases to a starting velocity of around 1100-1200 fps, and they worked pretty good up to around 50 yards. They leave a lot to be desired on the damage to the vitals, but they will shoot through a deer at normal angles.
