Most of the best telescopes don't brag on the box about their astounding magnification. Most quality scopes will use the objective mirror or lens measurements as a way to tell how good they are.
In Astronomy, a high magnification is not necessairly a good thing. Contrary to popular belief, most observable objects aren't all that small, they are just very faint. With a given 4" reflector and 10x magnification, the Andromeda galaxy is wonderful to view, but with a 100x magnification, you won't see much. As you zoom in, the less bright the view is. That is not good for space observation. High magnification is more useful for viewing Jupiter and Saturn. They are bright enough to hold observable levels of light even at high magnification. At these high levels though, the earth will shift the image out of the viewfinder every few seconds or so, so you need a motorized mount.
For rifle spotting, the scope will be used during bright times. Therefore, you can zoom in pretty good as still have plenty of light to observe. If you try to spot a target on a bright sunny day with a 4" mirror, be careful for your eyes! A LOT of light is collected, and at low zoom levels, it may be too bright to view.
I have used a $99 Bushnell 12-40x44 Refracting scope to spot with, but when the weather is hot, the heat waves blur the holes too much anyway.