I have a rather nice pair of Japanese 20x binocs, 56mm objectives as I recall. Pretty good optics for the under five hundred dollars category. I've been using them on a tripod, in lieu of a spotting scope for years, and I hate them. Let me count the ways:
1. I can see about the same, or slightly more, detail with the 20x binocs than with my 14x rifle scope, which means it is of little optical value, but does allow someone else to spot for me.
2. Bullet holes at 300 yards? Uh, no. Not without far superior optics. 30 cal holes at 200, barely and only in the very best lighting conditions. Shoot-n-see will improve this slightly.
3. Eye relief. This is where I get crazy. We all shoot with safety glasses, or at least that's what 100% of all shooting manuals and various owners manuals say, and 100% of all ranges and shooting clubs say, yet EACH and EVERY ONE of the spotting scope I've looked at in the stores has the same, ultra lame, ultra short eye relief that my binoculars have. If you can't use a scope at any and all settings while wearing glasses and while not touching it with any part of your body (if you're touching the scope, its jumping all over the place, and you can't see the detail its capable of showing you. At 300 yards, you'll need all the quality and detail possible. Do not touch the scope) it is 100% unsuitable as a spotting scope.
I completely fail to understand what it is that the spotting scope makers think we are doing with a spotting scope. Maybe I'm dumb, but I thought is was to spot our shots, so we don't have to walk 600 to 1200 yards round trip for each shot. We're wearing glasses 100% of the time, and that we want to see bullet holes. The 100 dollar "spotting" scope you see in the stores will show you less detail than a good rifle scope and therefore are 100 dollar paperweights for your office desk.
At 100 yards, any good binocs will work ok for you. At 300 yards and beyond, you want the best of the best, but they’re going to be dedicated for spotting. Anything over about 10X gets to be a pain in the neck for the uses to which binoculars are normally put, so you might as well get a real spotting scope, where you're paying for one set of really good lenses instead of two sets of mediocre ones.
In the final analysis, its getting cheaper to install a video camera near the target, with RF link to your shooting position, than to get super good optics.
I'm interested in trying some of the clestial telescopes. A decent reflector isn't expensive, just really, really big...