Fixed objective vs. adjustable objective

P

patchhounder

New member
I was wanting to know what the pros and cons are on an adjustable objective scope. Any help and information is greatly appreciated. Thanks.

JOSH EYE
 
I use AO Scopes on everything..., even my.22 LR's

AO is all about accuracy. For optimum accuracy you need to have the ability to elimanate parallax at a given range! This is generally only possible by fine tuning the optics focus, which brings us back to AO. The only possible "con" regarding AO that I can think of would probably be having to do the AO adjustment quickly in the field, but now that so many Scope Manufacturers offer "Side Focus" (My personal preferance) this makes focus adjustments much quicker & easier, most of the time without even breaking you cheek weld!!
If you only shoot at one particular distance +- a few yards, and your Non-AO Scope if factory set "Parallax Free" for that distance, then your all set......, otherwise AO is a must IMHO!!

Hope this helps!! /ubbthreads/images/graemlins/grinning-smiley-003.gif
 
On my hunting rifles I do not use AO scopes, it seems most times things are happening to fast and not knowing which direction and distance you might have to shoot adjusting an AO will add precious seconds to the shot. The scopes I use for hunting are Meopta 3-12x40 with a #4 recticle.
 
Don't meant to hijack the post but I have a quick question. If you set your AO for 200 yards does that mean it is paralax free 200 yards and in, or only at 200?

t/c223encore.
 
Quote:
Don't meant to hijack the post but I have a quick question. If you set your AO for 200 yards does that mean it is paralax free 200 yards and in, or only at 200?

t/c223encore.



just because the setting says 200yds does not mean that it is actually paralax free at 200. Most of the leupolds I use are off as much as 50-100yds. Put your rifle in bags and look at a target at 200yds, move your head up and down a little bit while looking at the target and adjust your paralax until your crosshairs don't move when you move your head. Now your paralax is set for 200yds no matter what the setting on your dial shows.
 
I use AO's on almost every gun I own. I tend to leave the objective on the all purpose setting or 50yds when hunting and usually don't have any problems. I did replace an AO scope with a non AO on my night hunting rig, because it was just to much to mess with at night and caused me a couple of missed opportunities.
 
It depends on the hunting situation. For fairly static situations where you have plenty of time to fuss with properly adjusting an AO scope they can be a positive addition. I honestly can't think of many hunting situations where you actually have that much time. Well except for colony varmints like Prairie Dogs or any of the other ground squirrel shoots. Woodchucks and Marmots or even jack rabbit shooting would work.

I am not a fan of AO scopes for my type of Coyote hunting. I don't like the size or weight of an AO scope, I don't like the fiddle factor of an AO scope, I don't think you need an AO scope at all for my type of Predator hunting. I say my type of hunting because if there is one thing to be learned on these internet boards is that coyote hunting is not the same everywhere you go. What I need down here near the Mexican border is much different from what works well in the wide open plains or in the deep woods. For mean AO on a coyote rig is nothing other than a big pain.
 
I totally agree, what the numbers say on the adjustable objective means nothing to me. They may as well not even be there are far as I'm concerned. Just turn the objective until things look good, don't worry about what it says. IMHO, on scopes of 10x or less, an AO is neither needed nor wanted. I have however, seen scopes of higher power without AO's, that desperately needed them. The new Leupy VXIII 4.5-14x40 non AO definitely comes to mind...---2MG
 
Those numbers on AO scopes don't mean anything to me either because I refuse to own a scope with them. Maybe if I had a dedicated P-dog rifle (ain't gonna happen), but no way on a big game or coyote gun. K.I.S.S.
 
I had one of the above mentioned 4.5-14 non-AO Leupolds...just sold it. It never caused me to miss anything I shot at, but it was also difficult to shoot small groups with it at 100 because of the paralax. I put a 4.5-14 with an AO on it and it shrunk my groups in half. *qb
 
An adjustable objective can be a real asset on a bench rifle at known distances. Just don't expect the marked distances on the scope to be correct....you'll generally have to find the real points of zero parallax at a known distance by the old "moving reticle" method.

On a hunting scope, they're just about useless unless you can get the game animal to pose for ya' while you "dial him in". I've never been very good at doing that, so I don't worry about or find a use for an AO scope on my pure hunting rifles.

JMO - BCB

2MG: Good to see you posting. /ubbthreads/images/graemlins/grinning-smiley-003.gif I thought maybe you'd become a nun or something the past few weeks....
 
A lot of my IA hunting is spot-stalking. When laying down to shoot I set it to the distance that I think it is at. (it is good to know I have to check the parallax) If I am trailing an animal I just leave it at 200-250yds, I figured it would be less of a problem at close range, than to be off at long range? T.20
 
I see no reason why you would need an AO to shoot consistently small groups, as long as you can see the target just fine. Like my old pal BCB said, on the bench they can be a real asset, but in the field they can be a real pain in the asset. BCB--have been way busy lately. I went and did a 42 day straight job at a nearby nuclear plant, working 72hrs/week. Had two days off, now back to working for myself and already have about 30-40 days of work lined up. Just ain't enough hours in the day lately. Yesterday, the wife and kids took off to Ohio, so I blew the day off! /ubbthreads/images/graemlins/shocked.gif Take care, I'm off to finish a job and collect some dough---2MG
 
Bench or field..., Parralax can make the differance between a hit or miss!! More so then most shooters realize, especially small targets at extreme distances!!

As far as small groups go, I'm talking about consistantly small groups at a variety of distances all with the same rifle/Optic set up.

Sub 1/2 MOA @ 100yds
Sub 1 MOA @ 200
Sub 2 MOA @ 300

Personaly don't see how this can be achived with out having the ability to eliminate Parralax!!

Below is a link about Parralax for those who don't completely understand it and it's optical effects.

http://www.6mmbr.com/parallax.html

 
If you have consistent gun placement, you weld your face on the stock consistently you can be very consistent. Sloppy gun control rarely makes for good groups. Another thing to consider, a coyotes kill zone is a great deal bigger than the 1/2" group you guys are punching on paper. I suspect that this is a typical "ya but!" type arguement. You know what I'm talking about "I shoot coyotes all day with a gun that shoots 2" groups", "ya but, my rifle shoots 1/2", "ya but, you don't actually need a 1/2" gun", "ya but, my gun is far better that yours", "ya but, I killed 2x the number of coyotes you did last year", ya but, ya but, ya but, ........ Most hunting situations don't need either high magnification nor an AO adjustable scope, I'd also be willing to bet that more animals are missed due to a seriously out of focus AO scope than any parallax error in a non AO scope. Okay OKay I can hear it all right now ya but, ya but, ya but, ya but ....... In the end you will do what you will, its up to you.

This reminds me of an engineer I once knew. One engineer I knew was trying to close a survey loop on a series of manhole covers, no matter how he tried he couldn't get to close within 0.50", he was going nuts, so he went to an old engineer to find out what he was doing wrong. The old engineer took one look and said "So, you are 0.50inch off at the end of a manhole loop ....... Do you think that 0.50inch error will make it difficult to find a 3.0 foot manhole and is it worth the time/money needed to find the error?" THe younger engineer put the problem asside and spent his time on something more important.
 
Back
Top