Killed two deer last year with a 30AW open sites 30/30.
One was a trotting shot on a doe at about 20 yards. The other about 80 yards on a doe I spotted in a clearing.
Optics may help improve your chances in low light, and with open sites you will benefit with good or corrected vision, but never underestimate the effectiveness of good sites if you know how to use them.
