That's pretty much spot on for a description. The other thing the A/O scopes let you do is shoot close up with a higher power. When you get closer than your scope is pre set for it effects it as well. Most shotgun and rimfire scopes are pre set to 50-60 yards, and others are around 100. Some companies will let you choose what you want and they will adjust it for you in thier shop.

I can shoot at 25 yards and 20 power if I want to and the cross hairs stay welded to the target as I move my head around. Most Air Gun target shooters use high power AO scopes to compete with for utmost accuracy. You have to set them up and verify the markings as well. The correct parallex isn't always what the numbers on the objective say they are.

The draw back to the adjustable objective type scopes is the focus changes at different distances and has to be adjusted. It's not to bad at the lower setting, but crank it up and 15 yards might make a difference. So these scopes work well for target and varmint type shooting, or maybe big game looong range type stuff. Where you have time to range your target and make adjustments. There is a trade off for precision I guess.

I wouldn't advise using one on a hunting rifle for big or dangerous game where you might have to make a quick shot. I tried to use one for deer hunting one season, I managed but it was sort of a pain. The next season my rifle was sporting a 3.5x10x50 with out the adjustable objective. If you have to make a quick up close shot and your parallex is set for farther a way you are screwed. You will pull it up and every thing will be blury. If you do use one, keep it on the lowest power setting and mid range objective setting, like around 100 yards or so. That way if you have to pull it up quick the picture will be pretty decent. And if you have time make any adjustments that you need. Just remember to put things back again after you shoot, or decide not to take the shot.

I have AO scopes on both my .22's and my .17HMR. My savage bolt 22 has a 4x16x50AO barska on it (Cheap, I got it used for 10 bucks!) My Marlin model 60 has a 2x7x32AO BSA air gun scope on it. And my Savage 17HMR has a 6.5x20x44AO alaskan guide scope from cabela's. But my remington inline muzzle loader sports a regular 3x9 type hunting scope for simplicity in the field. If it wasn't for the fact I hunt over a large meadow it would have a lower power scope like a 1.5x4 or something. That would be very fast and bright, perfect for deer hunting in southern MI woods.

Paul