I put a 3-9x40 on my Winchester 94 this year, and shot the largest deer I've ever seen on the property I hunt (a large 8-pointer), and a bobcat about 5 seconds later. One of the best hunting days in my life. The deer was 179 paces and the bobcat 109. No way I could have done that with my open sights, which are HiViz fiber optic sights I installed about 4 years ago.
It is heresy to mount a scope on a 94, if you have to drill and tap the receiver. I used an S&K side-mount though, which they just started producing. It mounted easily into an existing action screw slot and the 2 receiver sight slots. Check it out...
http://www.scopemounts.com