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Hi all

I am shooting in a 50 ft indoor league, shooting at official NRA targets. I got a Burris 6x Mini Scope that I use.

I crank the AO around until the target comes into focus, and this corresponds to '50' on the objective bell marking. This is yards, isn't it? (The markings start at 5)

The reason I ask, is that although the target is in focus, I still notice the crosshairs moving on the target if I move my eye. It is a little bit of movement, maybe a scoring ring or so, but thats enough!

I am working with it by trying to maintain a constant cheek weld on the stock, but man, I thought that an AO scope would eliminate this concern.

Thanks,

Trevor

PS I am shooting a GM 20" sporter weight barrel-what a magnificient upgrade-an immediate 60 point improvement (300 point course of fire) over the original 10/22 carbine barrel. I totally recommend one.
 

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Yes, the markings on A/O bells is almost always in yards.
The picture may be clear, but you should keep adjusting until there is no movement of the crosshairs.
I'm willing to bet if you take that scope to a 50 yard range and put the A/O on "50" then you'd still have parallax. Most scopes (even expensive ones) are at least a tiny bit off on their markings.
On my BSA 4-16x50mm scope, I adjusted the A/O until I had a clear picture at 50 yeards with no parallax. The markings on the scope said it was adjusted to about 30 yards:rolleyes:
 

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Parallax confused

Now I am confused!!
I have a Tasco WC 3-9X42 and it seems to have parallax problems of around 1/2 inch at 50m and was wondering about getting an AO scope to overcome this (I shoot at varying ranges).

However I have had some tell me that the AO only adjusts focus, not parallax. Can this be clarified??
 

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Parallax Adjustment

AussieJumper,
However I have had some tell me that the AO only adjusts focus, not parallax. Can this be clarified??
When one "adjusts the parallax" of a AO scope, one is focusing the 'image' of the target on the erector lens, where the reticle is located, either mounted or etched. This results in the 'image' of the target [now up-side-down] and the 'image' of the reticle being in the same focal plane for the ocular lens [eye piece] to view; being in the same plane, there is no relative movement between the 'image' of the target and the 'image' of the reticle as your eye sees it through the ocular lens.....! ! :cool:

Bottom line: The AO adjusts "focus" and "parallax" at the same time, if it is designed properly....! ! :)

Hope this helps....! ! :)
 

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Clarification

The AO adjusts parallax. There should be another movable adjustment that adjusts focus. Moving the objective changes the parallax, moving the eyepiece (I think cause I dont have one YET!!! But I do understand parallax) adjusts the clarity. I dont know if the "clarity adjuster" is called the eyepiece or what but the AO definately adjusts the parallax.
 

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Focus

Blackhawk,

The ocular lens [eye piece] adjusts the focus of the reticle.

This should be done once when you set-up the scope; it should be done by looking at a blank surface [so you ONLY see the reticle] like a flat wall or the sky.

Once this has been done, when you focus the AO on the target, its 'image' forms on the erector lens, where the reticle is located, and whalla, BOTH are in focus.....! ! :)

Setting-Up a New Scope:

AO = Adjustable Objective [the BIG lens up front]: The AO is used to focus the 'image of the target'.
Ocular = The eye piece of the scope [at the back end]: The ocular is used to focus the 'image of the reticle'.

If your 3-9X scope does NOT have an AO, and you are trying to use it at 50 yards, you probably have +/- 1/2" of parallax; centerfire [big game] scopes are focused at the factory for 100 to 150 yards, the normal ranges at which they will be used. When mis-applied to a rimfire rifle, parallax results, as most rimfire ranges are less than 100 yards......

Setting Up a new scope:
1. Inspect for any damage.
2. Are the AO and Power controls smooth?
3. Does the image appear bright and clear [the AO must be set for distance to the image]?
4. Focus the ocular lens on the reticle for your eye; not all eyes are equal, and this must be done. If you normally wear corrective lenses while shooting, then wear your glasses for this step. If you wear glasses for reading, but not shooting, then leave your glasses off for this step. When focusing the ocular lens, first look off into the distance for about a minute [so your eye accommodates to distance], and then quickly look through the scope at a blank surface [wall or sky]; is the reticle clear and crisp? If not, adjust the ocular lens 'out' 1/2 a turn, and then repeat; if it is better, then give it another 1/2 turn 'out'; if not, give it a full turn 'inwards'; repeat until you have a clear and crisp image of the reticle [ignore what the target looks like]. Remember, each time look off into the distance for about a minute before looking through the scope......
5. Adjusting the AO for target shooting: This should be done when you are at the range [or the place where you shoot]; initially, set the Power to its highest level, and turn the AO ring to the 'marked' range at which you are shooting; if your target is at 50 yards, then turn the AO ring to "50 Yards"; now look at your target through the scope: is it clear and crisp? If not, turn the AO ring ever-so-slightly to the left or right until your target is clear and crisp. Now, set the Power to the desired level. DONE, until you change your shooting distance.
6. Adjusting the AO for hunting: This should be done just before you enter the area to be hunted; set the AO ring for the range at which you 'expect' see game: squirrels - 50 yards; woodchucks - 100 yards, etc..
7. For Non-AO scopes [rimfire and air gun], steps #5 and #6 are omitted.
8. Sighting-in the scope is a separate issue.

Good Luck......

[Originally Posted by BigMike on RFC 2/28/02]
 

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)Thanks - that does help considerably

At the risk of opening a can of worms (and my rather thin wallet). If I investigate purchasing an AO scope that will of course do everything well and cost nothing. Any reccomomendations on:

1. Well priced sites that sell scopes and are likely to be able to ship overseas (Australia)
2. I then just need to decide which 4-12X40AO or there abouts is best for my needs (range 50 and 20m as well as in the field at dusk on rabbits). I'd do a Leopold VX3 but my budget does not stretch that far. I might have to scour the other threads in more detail, It sounds like the 44 Mag???? might be a good and affordable option. (Big Mike tell me if I am taking us off track here)
 

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Dawn and Dusk Hunting Scope

AussieJumper,

If you are primarily using the rifle [scope] for hunting, then the 4-12X 40mm AO size scope should do the job nicely. Where the higher power scopes shine is on the range shooting at 'itty bitty' targets [bullseye of .01" dia.]....! ! :)

For hunting at 'dawn' and 'dusk', get as big an objective lens as you can afford; relative brightness is a "square" function of the exit pupil:
Relative Brightness = [Objective Lens Dia./Power]² , where
Exit Pupil = Objective Lens Dia. in mm / Power

Even going from a 40mm to a 44mm increases the brightness by ~ 18%....! ! :eek:

Simmons 44 Mag Riflescope: 4-12x 44mm AO Rifle Scope - Adustable Objective - Wide Angle - Black Matte
All 44 Mag scopes have a non-reflective matte finish and duplex reticle. This target model comes with adjustable objective, raised elevation/windage knobs, 1/8 minute click adjustments, and is fogproof, waterproof, and shockproof. Sale! $119.00[at Natchez]

A few 'rules of thumb' on scopes:
Quality drives price...! ! :eek:
Buy by Model, NOT just Brand...! ! ;)
Power doesn't equal Resolution...! ! :(
Higher Power = Narrower Field of View.
Lower Power = "Faster" to pick-up game.
Larger Objective = Brighter Scope.
Larger Objective = Higher Cost... $ $
Made In China = JUNK

Places to look for a scope at a good price:

SWFA [RFC Sponsor]

Midway

Natchez
[WE ONLY EXPORT TO DEALERS] :(

This ought to get you started mate....! ! :)
 

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Thanks Mike

They are good sites - unfortunately none will direct ship to Outside US. We can fight a war (or several for that matter)together but we can't trust the logistics systems between the countries.

I might have to get creative!!
 

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Shipping to Australia

AussieJumper,

Sorry Mate.....! ! :(

Perhaps you could work a 'deal' through one of RFC Sponsors who ships overseas.....? ? Just a thought....... :)

The individual could buy the scope from "Natchez" and then, turn it around and reship it to you 'down under'....? ?
 

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BigMike,

Thanks for the detailed instruction and explaination. :t

Could parallax cause even more than 1/2" change in POI?

And would it tend to be a stringing affect or just a random change?
 

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POI Shifts Due To Parallax

Chum_Bucket,
Could parallax cause even more than 1/2" change in POI?
Yes, depending upon how far the scope's focus setting is 'off' the actual range; for a centerfire type scope ["DeerGetter"] focused at the factory for 150 yards: [conservative estimates given]
@ 300 yards actual range: ~ +/- 1/4"
@ 200 yards actual range: ~ +/- 1/8"
@ 150 yards actual range: ~ None <<<<<< Focus Point
@ 100 yards actual range: ~ +/- 1/8"
@ _75 yards actual range: ~ +/- 1/4"
@ _50 yards actual range: ~ +/- 1/2"
@ _25 yards actual range: ~ +/- 1.0"

The above is why we do not recommend buying the 'Mart' scopes for use on any rimfire; they are almost always a centerfire type scope focused for 100 to 150 yards, well beyond the normal rimfire ranges.....! ! :( :(
And would it tend to be a stringing affect or just a random change?
I would say "random", unless your rifle is consistantly shifting on the bags in only one direction, and uncorrected by not moving back to the rest's 'stop pin'.

Hope this helps....! ! :)
 

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"Side-Focus" scopes

I put the subject of this posting in parenthesis because the side focus knob is supposed to be for adjusting parallax. With my Leupold Long Range Tactical scope with side focus, the adjustment is so easy to make that I just twiddle the dial until the target comes into focus. Because you can run through the full range of adjustment so quickly, and without taking your eye off the ocular lens, one can readily see the focus change. Once the focus is clear, I then shift my head slightly, left to right, to make sure that the reticle is not moving with respect to the target (the true test for parallax.) Once you've gone through this exercise you convince yourself that adjusting parallax and adjusting true focus (not eyepiece focus) are synonomous.

Zirc
 
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