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Ignorant questions on scopes

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fastline View Drop Down
Optics GrassHopper
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    Posted: May/05/2012 at 10:09
So, my brother and I have been working on our .22s to determine how accurate the "gun" is.   We were  both sighting with bipolds.  Mine is a 10/22, his is a Savage bolt action.  Both with match grade bull barrels.  We were both surprised at how poor the groups were at 50yds with a wide variety of ammo to include Wolff match, Eley, Lapua, Remington subsonic, Federal, etc.  If I had to select one, it would have been the Eley.  Of 5 rounds, three would be touching, and 2 would be .75" away and touching. 

I think we are getting a gun vise today to try and secure the gun and take the scope and shooter out of the equation.  I was playing with my POS Simmons scope that I have on the 10/22 as well as my high end Leupold VX3 and I guess I never noticed that with both, if you move your head around behind the scope, you can actually move the reticle relative to the target....  That could be a huge issue we are having. 

I am curious how one works to eliminate this and what other factors we might be having?  This could be our issue. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Sapper524 Quote  Post ReplyReply Direct Link To This Post Posted: May/05/2012 at 10:33
Thats what they call parallax ... If the scope doesn't have an adjustment for it (front objective turns or a side focus) you can't do a thing about it.  Scopes like that have a fixed setting usually at 100 or 200 yards.  You can put some kind of reference on your cheek weld to try to duplicate it each shot.
 
If your scope does have an adjustment for parallax you set it, slightly move your head side to side or up and down (very small movements) and if the reticle moves .... adjust your parallax a little and repeat.  Once you can move your head slightly side to side and up and down and the reticle doesn't move ... your set.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote BeltFed Quote  Post ReplyReply Direct Link To This Post Posted: May/05/2012 at 10:47
Read my sinature line first, then consider that when you read my responseBucky
 
First your bipod, if not properly and consistantly used, it will have an effect on your groups.
 
Second is your parralax. I'm not the expert here for explaining the whys, and therefores, but the best I can explain is it deals with where your scope is focused. Most scopes have their parralax set at 100yds, meaning that the reticle and image are focused at that distance, and if you move your head while looking through the scope, the reticle will appear to stay on target. At any other distance, the reticle will appear to move when you move your head. Since most scopes below 9 or 10 power do not have or need a parralax adjustment it is impotant to have a consistent spot weld with the stock that places your eye in the center of the scope to remove any error in the parralax.
In other words, when looking through the scope, the image should be full and clear edge to edge, with no shadows on one side or the other, and what part of the scope tube you do see, should appear even all the way around.
 
Your rifle probably shoots fine, and your scope is not defective. You just need to know how to sight with a scope. It's not as easy as you'd think, but it is easy once you know how.
 
Your local prepert signing off.
Life's concerns should be about the 120lb pack your trying to get to the top of the mountain, and not the rock in your boot.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote fastline Quote  Post ReplyReply Direct Link To This Post Posted: May/05/2012 at 10:47
Should parallax settings need changed when the scope power is changed?  If that is the case, I might have my issue.  I believe I boosted my zoom and some of my problems started there. 

Regarding the parallax settings, this is separate from the "focus" that is a relatively new feature for lower end scopes?

Also, at what distance should the parallax be set?  reasonably close so you can really see it move, or at the distances you would shoot at? 

Thanks!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote fastline Quote  Post ReplyReply Direct Link To This Post Posted: May/05/2012 at 10:55
I guess I will have to school better on parallax.  I always understood it as the point at which would be the convergence of the image from the rear glass and would be where the eye needs to be placed relative to the scope (distance from). 

From what I already understand, the distance from eye to scope can also radically affect parallax settings? 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dogger Quote  Post ReplyReply Direct Link To This Post Posted: May/05/2012 at 11:00
Look under "FAQ" section in the Forum Home for more detail on parallax:

What exactly is parallax anyway?

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bitterroot Bulls Quote  Post ReplyReply Direct Link To This Post Posted: May/05/2012 at 11:06
Originally posted by fastline fastline wrote:

I guess I will have to school better on parallax.  I always understood it as the point at which would be the convergence of the image from the rear glass and would be where the eye needs to be placed relative to the scope (distance from). 

From what I already understand, the distance from eye to scope can also radically affect parallax settings? 
Forget the distance of your eye to the glass.
 
Two things are focused in the scope.  First is the reticle.  You focus the reticle by using the focus ring on the scope.  Focus the reticle once for your eyes and leave it forever.  I do this against a clear blue sky with the the image focus (either adjustable objective ring, side focus knob, or rear focus ring(only on sightron S3 fixed and SS fixed power scopes))  focused to infinity.
 
Then, when you are shooting with your target at any distance, use the image focus control (either the AO or side focus knob) to bring the image focus to the same plane as your reticle is focused.  Sapper's technique of looking for reticle movement on the target while moving your head behind the scope is the technique I use as well.
 
If the scope doesn't have a image focus control, it has the focus set at a certain range to eliminate parallax error.  The scope then depends on the depth of field of the system to keep targets in focus at different ranges.  This will allow some parallax error at ranges much closer or further away than the scope's setting.
 
If you keep your eye perfectly centered in the exit pupil of your scope, there will be no parallax error, regardless of setting.
-Matt
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Post Options Post Options   Thanks (0) Thanks(0)   Quote fastline Quote  Post ReplyReply Direct Link To This Post Posted: May/05/2012 at 11:23
Ah, so the adjustable objective (AO) either on the front glass or side by the turrets will both adjust the focus but more importantly adjust for parallax errors at different shooting distances?  IE, adjustable objective is paramount for tight groups at various distances?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote stickbow46 Quote  Post ReplyReply Direct Link To This Post Posted: May/05/2012 at 11:24
If you have a parralex turret or an AO on the front of the scope the first proceedure is to get your rear reticle aligned with your eye.The way to do this is to look at a clear sky or a blank wall,make sure the maganification of the scope is at it,s max.A 3-9 scope max would be the 9 power.Turn the rear occular [diopter ring]till the reticle looks very sharp,do this at least 3x.
 
Once you have the diopter set don't touch it any longer.All your clarity adjustments will now be done using the parralex adjuster.All those numbers on the side are only a starting point,for the fine tunning just keep turning the adjustment till it looks clear & if it is when you move your head up & down or from side to side while looking down the scope towards your target the cross hair should remain stable & not move! If the cross hair moves continue moving the parralex till the cross hair is solid as a rock.Again do this proceedure with the scope set at max magnification.
 
There also a very good expination of what parralex is on the forum home page.Hope this helped!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote RotoReuter_DM Quote  Post ReplyReply Direct Link To This Post Posted: May/05/2012 at 11:34
If you're shooting for groups parallax adjustment is pretty important. On a 22 I'd get one that focuses down to 10 meters like the fixed SS models.

Like others have mentioned constant cheek weld will eliminate the effect but that's tough to do all the time and in different shooting positions.

For me having parallax adjusted correctly is enough of a reassurance that I seem to shoot better with adjustable parallax.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote fastline Quote  Post ReplyReply Direct Link To This Post Posted: May/05/2012 at 11:36
Yep, i am reading the sticky links posted.  Sorry for the likely redundant questions. 

So should the zoom or power range change the focus setting of the scope?  IE, if I change the power of the scope, do I need to readjust the objective as well? 

I was looking at the 4-16x50 Mueller scope but may just get spoiled having the side focus on the Leup VX3.  That would certainly be faster to adjust..
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Post Options Post Options   Thanks (0) Thanks(0)   Quote RotoReuter_DM Quote  Post ReplyReply Direct Link To This Post Posted: May/05/2012 at 11:38
The zoom should not effect parallax other than the higher the magnification the easier it is to see the error.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote fastline Quote  Post ReplyReply Direct Link To This Post Posted: May/05/2012 at 12:04
I think we will take a look at parallax concerns and bipod issues today.  I know my stock runs VERY close to the barrel it might be that when I "load" the bipold, the stock gets into the barrel.  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dale Clifford Quote  Post ReplyReply Direct Link To This Post Posted: May/05/2012 at 13:08
as bitterroot mentioned if your behind the optical axis there will be no parallax. What your experiencing is more than likely wind changes, either to the bullet, or directly hitting the shooter. 50 yds is also the transition point of a lot of 22 lr bullet going from supersonic to subsonic. Which is why alot of long range shooters use subsonic 22. If you use a standard velocity 22 that groups good as 100 yds. , it is more than likely gone sub before target and will work good for long range 22 stuff.  (300 yds). 
a shooting technique which you can use to eliminate parallax, although not convenient for constant use- makes use of the eyes remarkable ability to center things. move your head back on the cheek rest until you see two circles-- one the scope ocular and the other the small ring of light containing the target and cross hair, center everything and shoot. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote fastline Quote  Post ReplyReply Direct Link To This Post Posted: May/05/2012 at 14:30
All the stuff we are shooting is staying subsonic through our 18" barrels.  I have some hotter CCI stuff but these are designed to be whisper rifles. 

I did determine that my assumed floating bull barrel was not floating at all so I just redid the stock to float the barrel.  The beauty of synthetic stocks... I have to wonder if I was tweaking the barrel when I load up on the bipod. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Dale Clifford Quote  Post ReplyReply Direct Link To This Post Posted: May/05/2012 at 15:34
have you chronographed them?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote fastline Quote  Post ReplyReply Direct Link To This Post Posted: May/05/2012 at 15:40
Through my bros gun, not mine.  Most in the 950-1050 range.  The Federals were turds.  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote fastline Quote  Post ReplyReply Direct Link To This Post Posted: May/06/2012 at 11:43
We made it out to test yesterday with a new gun vise.  Unfortunately the vise would not hold the gun still enough to get repeat shots without adjustment but would certainly hold it still.  Shooting my bro's Savage, we would get .5" groups of 4 and then a spoiler being over 1" off!  We still have not totally isolated the optics due to the gun moving a bit. 

At this point, I am ready to install a laser which should not move.  I have never seen such inconsistency from a gun.  I can stack bullets on top of each other at 100 with the .308 FCP but that has a Leup VX3. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SVT_Tactical Quote  Post ReplyReply Direct Link To This Post Posted: May/07/2012 at 08:09

I did this test a while back with 22 ammo and might be helpful for you

http://opticstalk.com/topic23086_post305321.html#305321
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