Re: Adjustabel Objective AO
Used to be that any scope over about 9 or 10 power came with an AO. Recent years, they've began making some that are 12, 14 ect without them. Don't ask me why, that's a question for the marketing crowd.
Personally, I wont buy a scope without an AO or SF unless it's a low power scope intended for use only out to about 300, maybe 400 yds.
Most scopes are designed to be "parallax free" at a certain distance. They come from the factory preset for somewhere between 100 and 150 yds usually.
What this means is that if you're shooting at 50 yds and the scope is parallax free at 150....you will have to have your eye perfectly centered in the field of view or the crosshairs will "wobble" back and forth as you move your eye back and forth. Parallax; It's like looking at your speedometer from the passenger side vs the drivers seat. The speed isn't changing, but it appears to be.
An AO or SF allows you to set that "parallax free" distance to your liking, you are not limited to the factory preset 150 yds. Very helpful with high powered scopes, long distance, small targets, and very close distance too.
Aim small = Miss small