Just to throw another personal experience in. My girlfriends father shoots a Sako .222, from the 60's, with about 10,000 rounds through the thing (Can't believe the thing still shoots) This year, he lent the rifle to a close friend who lived north of us here in Caledon, and he and a friend filled both their buck tags with the rifle. The first was a smaller buck, who he was not worried about ruining the front cape. He shot it in the neck at around 90 yards, and it dropped in its tracks, dead as a doornail. The second buck just won the Standard Antlered Buck Draw for 2013, and scored 210 Points when scored in his area. The buck was massive, and weighed around 260lbs. He shot the buck just behind the front shoulder, and hit it through one lung and broke the shoulder on the far side. The buck ran around 40 yards and dropped in his tracks as well.
I would have to say that, the most important thing is to choose the correct ammo and make great shot placement. Vital shots are very important, or a neck shot if you feel comfortable enough doing that. Shooting a high expansion bullet, which in this case was a 50 Grain Winchester Pointed Soft Point bullet, causes a great deal of damage and opens up a large wound on the far side of the shot. Great blood trail, and terrific damage within the good ol' boiler room. Hope this helps, just throwing in my .02!