The 168 gr MatchKing is NOT a good bullet for deer hunting. While very accurate, the MK is not designed for the amount of expansion of regular hunting bullets.

As for the original question in this thread: You have to choose what best fits your needs and hunting style. There is no one "best" caliber for deer hunting. If you will be hunting in places where the furthest shot you will take will be around 100 yards, there would be no sense in getting a belted magnum. Conversely, if you are hunting in an area where a 300 yard shot is possible, you want the power of the belted magnums.

I have three different guns that I deer hunt with. Which gun I use depends on where I'm hunting. For longer range shots, I use a 7mm Rem Mag. For medium range action I use a .308. If I am hunting in thick areas where shots won't be of any great distance, I use a 7.62X39 (SKS) with open sights.

First and foremost, always use quality hunting ammo regardless of what kind of gun you get. The optimal bullet weight for a white tail deer is 140-150 grs.