RE: Killing distance
Fuzzy,
Josh said it pretty well. I practice all year long to be hunt ready shooting not only 3-D, but target archery out to 80 yds. I pretty much limit myself to 20-25yds when hunting. I also think it depends somewhat on what type of game your hunting. A shot at a 100# whitetail is much different than an elk or moose where the kill zones are larger.
As far as your friend missing that happens to us all. There are those who have missed, those who are going to miss, the rest are lying! When I shoot compound I'm a whole lot more accurate at longer ranges. Where we hunt a shot over 40yds is unusual, but out west its quite common.