....... Do you think a 50% hit rate is acceptable for rifle hunting?.....
Personally I would hope that anyone who decides to do much BG hunting can do far better than that. If a guy kills a couple hundred head of BG animals in his life and misses 50% of the cold barrel 1st shots (regardless of distance), it's a pretty sorry showing.
I would say that a shot at an un wounded BG animal offering no better than a 50-50% chance of success should be passed up.