Adjustable Objective

[Robert]

So how does an Adjustable Objective scope work, and why have I read that they are a pain in the neck and not worth the effort? I am kicking around the idea of putting a scope on my FAL and my friend suggested a fixed 15x that he has and seems to like. Never having seen the scope in person I am wondering how the AO works.

 

[Zak Smith]

The adjustable objective is most often to set the parallax-free distance to the distance you are currently shooting at.

Most "side-focus" knobs adjust both focus and parallax.

 

[Robert]

Thanks Zak.

 

[browningguy]

A fixed 15x is really for very long range target or prairie dog type shooting. They are great for that, but at short ranges many people find that they magnify your wobble too much and are distracting. Add to that, most FAL's can't really take advantage of the high power optics , accuracy wise. You might be better served with something like a fixed 2.5 or 4x scope, or a low power variable such as 1.5-4.5, or 2-7. I use a 2-7 (Leupold)on my .458 Winny, and a 1.5-4.5 (Burris) on my .50 Beowulf upper and find it perfect for shooting out to 100 yards, on a flatter shooting round it's fine out to 200 at least.

 

[Kymasabe]

I have 3-9x40 AO's on both my Ruger 10/22 and my Saiga 7.62x39.
I like them becauseI can shoot at 50,100, or 200 yards paralax error free.

 

[Walkalong]

Unless you shoot competitively or shoot varmits at long and varied ranges there is no real need for a parallax adjustment on your scope. It just doesn't make that big a difference in the real world. I wish I could remember where to link you to a good article about it.
For hunting you are not going to have time for it and the miniscule error you may encounter due to parallax is not going to make any difference. Hesitating to adjust it will.
The gun rags have everybody thinking they need more power and bigger objectives and parallax adjustment when you just don't.
Better glass will do more for you than a bigger objective of poor glass. Buy the best glass you can afford and a reasonable power range. My .308 has a Vari-X III 2.5 to 8 w/ 32mm objective and it beats MANY 50mm objective scopes looking into shadows and at dusk. Will it beat the same quality glass in a 50? H*** no, but you get the idea.
My benchrest guns Leupold uses a sunshade to keep light OUT and has to be parallax adjustable to compete. Different game entirely.

My scope advice. Put your money in the glass, not the features. Buy glass till it hurts a little. The pain will subside and you'll be happier.

 

[nplant]

Generally speaking, anything much over 8-10x will magnify wobble (as previously stated) to the point of distraction for most, as well as magnify any effect of mirage at long distance and make you wish you could back off a bit.