Your questions are a little too general. For shooting big game, 20X is more than enough. Just a couple of days ago I was sitting up on an ambush spot with a view of ranges from a couple hundred yards to about 1500 yds. So I decdided to do some "scoping" wiht my NF 5.5-22 set on different powers at different ranges. My conclusions.... 5.5x through the NF is more than adequate for deer size or bigger game @ 1000 yds.