Zeroing a scope and adjustable Parralax

[TaxiDriver]

My local RFD zeroed in my Hawke AO scope the other day using a gizmo that used a sort of target holder/grid thing that fitted in the end of the barrel and then holds a card on which is a tiny squared grid, you then adjust the scope up/down & left/right so that the crosshairs of the scope fall on the centre lines of the grid (with me so far ?) this is done with the scope set to 100yrds.

 

If I understood the idea correctly, the scope is zeroed at 100yrds and then when you adjust the parralax down(for example to 30yrds) it should maintain zero at 30yrds ??

 

Trouble is,......... I now can't hit a barn door at 30yrds never mind a rabbit or pigeon :no:

 

Before I go back to the RFD, Have I misunderstood the principle/idea of the adjustable Parralwotsit ?

[Glenshooter]

Since the trajectory of the bullet/pellet has to rise to the 'sightline' to reach zero it then falls to cross the sight line again. This is the primary zero, which in your case appears to be 100yds. But the secondary zero is then around 30 yds, but this depends on a number of factors - rifle, scope height, bullet velocity etc

 

But suffice to say, there are two zeros. Hope I have read your question properly.

 

See here for a better description - http://www.arld1.com/trajectory.html

[Devon Fox]

They used a bore sighter - they will get a new gun/scope on paper, but they aren't 100% so you will still need to zero the gun - punch some paper and see what's going on.

[UKPoacher]

My local RFD zeroed in my Hawke AO scope the other day using a gizmo that used a sort of target holder/grid thing that fitted in the end of the barrel and then holds a card on which is a tiny squared grid, you then adjust the scope up/down & left/right so that the crosshairs of the scope fall on the centre lines of the grid (with me so far ?) this is done with the scope set to 100yrds.

 

If I understood the idea correctly, the scope is zeroed at 100yrds and then when you adjust the parralax down(for example to 30yrds) it should maintain zero at 30yrds ??

 

Trouble is,......... I now can't hit a barn door at 30yrds never mind a rabbit or pigeon :no:

 

Before I go back to the RFD, Have I misunderstood the principle/idea of the adjustable Parralwotsit ?

 

Best thing is to forget the PX for air rifle distances. Set the zero around 33 yds for a .177 or 27 yds for a .22. Adjust the rear eye relief to mid setting, adjust the PX to around 22 to 25 yds and leave it there. You can make quick adjustments using the rear focus and it is a lot easier then messing with the front PX when a target presents itself.

[FalconFN]

You will need to zero your scope to your prefered distance, say 30 meters as parallax adjustments only affect the apparent position of the crosshairs if you move your head around.

 

Zeroing your scope to 30 meters and Setting your AO to 30 meters should negate any parallax errors.

 

I'm not sure why they set your zero at 100 meters. :blink:

[TaxiDriver]

Sounds like I'd be better throwing the dam gun at the target then

[FalconFN]

Since the trajectory of the bullet/pellet has to rise to the 'sightline' to reach zero it then falls to cross the sight line again. This is the primary zero, which in your case appears to be 100yds. But the secondary zero is then around 30 yds, but this depends on a number of factors - rifle, scope height, bullet velocity etc

 

But suffice to say, there are two zeros. Hope I have read your question properly.

 

See here for a better description - http://www.arld1.com/trajectory.html

They should have set the primary zero at 30 for an air rifle so the secondary would be around 15 meters.

[TaxiDriver]

They should have set the primary zero at 30 for an air rifle so the secondary would be around 15 meters.

I'm confused by this primary and secondary zero business :unsure: :unsure:

 

Am I wrong to think that the pellet is leaving the gun straight and after a while begins to drop ? One of the earlier replies here gave me the idea that what they were saying was that the pellet leaves the gun and climbs then begins to fall again ?

 

I'd like to be able to shoot out to 30yrds for rabbits and squizzers, as thats about the safe effective range of a <12ft/lbs air rifle and also of my new red led torch.

[Cannon]

I'm confused by this primary and secondary zero business :unsure: :unsure:

 

Am I wrong to think that the pellet is leaving the gun straight and after a while begins to drop ? One of the earlier replies here gave me the idea that what they were saying was that the pellet leaves the gun and climbs then begins to fall again ?

 

I'd like to be able to shoot out to 30yrds for rabbits and squizzers, as thats about the safe effective range of a <12ft/lbs air rifle and also of my new red led torch.

 

A .22 pellet will have a 'lobbed' trajectory meaning it climbs then falls after leaving the barrel. If you have zeroed your scope the pellet will cross the horizontal crosshair twice in a single shot at two different distances. Easiest way to check your zero is to get the gun on paper at 10 yards. Once you are able to hit the same spot time after time at 10 yards, move it out to 20. You will then find you may have to adjust your windage and elevation on the scope, but it will be a lot easier and quicker as the point of impact should not vary too much from 10 yards. Just work your way up to 30 in 10 yard increments. You can use 5 yard increments if you find it easier.

[UKPoacher]

Load the Chairgun program and you'll get the picture. http://www.chairgun.com/

 

Basically the scope's view is straight and angled slightly down from its position at the top of the barrel. The pellet appeas to loop up and back down through the scope's field of view over 25 - 40 yds depending on calibre, power, etc. Where the pellet's path cuts through the scope's view are the points of impact - primary and secondary.

[kent]

Bore scoping is generally a waste of time especially with air rifles. One should say riflesmith, gunsmith, gunshop, gun seller and shop assistant this is in decending order of worth letting actually touch a rifle

What you need to do is get it on paper and actually set it up like this

 

 

1. Take a large sheet of paper (backing wallpaper is ideal or a large piece of cardboard) and set it up vertically 8yds from were you will shoot initially, remember backstops. Mark a totally horizontal line down the centre and one vertically across so you end up with a large cross. A spirit level is good for this

2. your aim point will always be the cross centre. Ensuring your gun has a full fill if precharged choose a good steady firing posision and fire three shots all aimed at the cross centre. look at were those shots ended up and work out were the centre of that "group" is with luck you are looking at one raggy hole. Mark a cross in pen through each shot and measure distance from the cross centre you aimed at to the group centre.

3. to adjust you scope remove the turret caps and note the calibration most are 1/4" movement at 100yds per click approx 1/4 moa commonly. At 8yds thats hardly going to move your shots! but to explain 1/4" @ 100 yds = 1/8" 50 yds = 1/16" @ 25yds etc. ok now turn your turrets the estimated amount ensure you do this the correct way

4. shoot another group of three, put crosses through them and adjust again as required- did you turn them the correct way? do this as many times as required to get you group dead on centre.

5. Ok now to check your scope and gun barrel are in perfect vertical alignment. Move the scope upwards to its furthest extent and shoot a group then move it all the way down. All the time ensure your vertical reticule or crosshair is actually totaly vertical. If these two groups both split the line everything is fine, if one is to the left and the other to the right the scope is scew in the mounts and the mounts need a slackening and the vertical plane correcting by rotating the scope slightly till you can complete this exersize. now return to the vertical zero you had

6. The reason we set off at 8yds is to remove as much as practical the effect of wind on the pellet and check alignment. However we must now select a normal zero range to set the elivation of our groups or height if you like to get the best use out of our guns trajectory. All amuntion fired from a gun is subject to gravity and as such the farther away the target the greater we need to aim high it is this curved path of flight that i refer to. for a .22 cal this range is normally best about 30 yds and for .177 about 35 yds but velocity and scope height over the barrel bore can effect things. So with your new selected range repete the earlier proceedure of adjustment, however if your cross hair was set up perfectly vertical you should not have to alter the left or right settings. Your group might be off centre but ignoor it for now if all your groups go slightly to one side it might be because of wind drift if outside. only if you are indoors should you question it- still it could be created by bad marksmanship pulling to one side etc. so just adjust the scope settings for pellet impact height only

7. Your not quite done yet! Get a pad and pen mark a list of assending ranges 5yds, 10yds, 15yds,20yds,25yds,30yds,35yds,40yds,45yds. set up targets at all these ranges and shoot a well aimed group at each and record the results in you pad as regards impact high or low. Athough not stictly part of zeroing this plots the rise and subsequent fall of your pellet through the "line of sight" you should find something like 15 yds your shots go high and 45 yds they go low. This is normal

 

If your struggling remember with a pcp presure drop and hence velocity drop will make shots go progresively lower and on spring guns the act of the gun recoiling could keep moving your scope and hence zero.

 

Hope it helps, i was just bored tonight

Edited March 18, 2011 by kent

[hoTshoT-16]

ACCURACY OF MY R-10

ZEROED AT 40YDS AND SHOT IN WIND

 

[TaxiDriver]

Sounds like I'd be better throwing the dam gun at the target then

Well, I've downloaded the Chairgun programme :unsure: So thats all good, Something else on my hard drive that I don't have a ******* clue what to do with

 

So, its back to the big bit of paper at 35yrds and fire of enough shots to get some on the paper and start from scratch then ?

but should I set the front Parallax adjustment to the distance I want to zero in at or infinity or...........

 

I can see the start of a 'For Sale' thread looming.......Game SFX Used solely for weight training & throwing at barn doors

[TaxiDriver]

ACCURACY OF MY R-10

ZEROED AT 40YDS AND SHOT IN WIND

Ohh shurrup, nobody loves a show off

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:P :P

[pabs]

The chap that 'zeroed' it was only getting it on paper for you. You need to fine tune it. Bung a big bit of paper up at 30 yards and start shooting......

The post that Kent put up is good advice. But to start with just zero her for 30, then try some groups at 15 and 50. You might get lucky and all will be well and you won't have to start fiddling with the scope to get alignment right.

[Largerider]

Have a look at this.

 

when you get it near start to shoot 4-5 shot groups, make sure you keep aiming at the same spot as this will give you an better idea than just single shots. it's easier to do the initial zeroing on a target set at 10 yrds and then move it out to 30yrds.