Are these the old style winchester silvertips, or the new style combined technology winchester/nosler ballistic silvertips?
The old style ones are reputed to be a good solid bullet, although I've never used them. The new ballistic silvertips were, in my experience (Mule deer shot approx 200yds, 130gr. 270win) garbage. Penetration was extremely shallow, there were no significant fragments of the bullets left. Shrapnel managed to penetrate the diaphragm and puncture the stomach (both bullets entered just behind the shoulder, broadside). It made the deer dead, which some would call success, but it did not perform in the manner I would consider acceptable.
Good bullets for coyotes. Not deer, and definitely not moose or elk, IMO.