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PostPosted: Fri Jan 05, 2018 5:57 am 
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I'm at my wit's end to understand why I'm sometimes getting large vertical errors that I don't perceive at all on shooting. I shoot .22 indoors at 25 yards, and at present I'm generally shooting around 97 or 98. But sometimes weird stuff happens:
(1) twice recently (once on a sighter, but once on a comp card) a shot has gone high at 12 o'clock into the 6 ring (!!!), and I had no idea till I saw it.
(2) this week I had a card where I was on the sighter, but then the first diagram dropped at 6 o'clock into the 8 ring; back to the sighter and was on it, but the second diagram again dropped into the 8, and the rest of the card fluctuated badly, producing something catatastrophic like a 92.

It's cold at present, and I think things get worse when it's cold - maybe I start shivering, or at least my sling arm tenses? - but the completely weird high shots were at the beginning of the session.

I'm left-handed, and I shoot with a MEC lens on a head-band for my aiming eye, in case that's relevant. The rifle is new last year, Anschutz barrelled action in Esprit Carbine Universal Concept stock.


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PostPosted: Fri Jan 05, 2018 6:23 am 
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Location: France
What ammos are you using ?

Try first to fix your rifle, with a clamp or Hunter bags/rests. On a blank target, shoot severals bullets.
If the vertical dispertion happens, try others 22lr brands/models.

If not, then that's your position. Before each shot, check carefully that your buttplate is always set the same way on your shoulder, and same thing with the cheekpiece.

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PostPosted: Fri Jan 05, 2018 10:28 am 
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be sure your bedding screws are not contacting the action.


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PostPosted: Fri Jan 05, 2018 10:45 am 
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Location: Taunton, Somerset
Jedin,

I don't think your problem is ammo related. At 25 yards most quality ammo (Eley, RWS, Lapua) will hold the NSRA 10-ring; Sport won't group tightly enough to give a high average, but it's not 8-ring bad - unless pointed there. I'll assume you're not using bargain bucket junk like American Eagle or T22, which does produce audibly loud and soft shots, going high and low, together with excessive dispersion anyway. You may occasionally find a duff round even in good ammo like Match, but not to the extent you report. You don't mention cleaning, but a good brush won't hurt. Don't forget the tube if you have one fitted.

As noted above, ensure sights, buttplate, cheekpiece, and the bedding bolts, or barrel clamps are tight. Not sure what torque EC recommend for barrel clamps, but Anschutz suggest 6Nm for metal stocks. A different torque may give better accuracy, but a standard setting is unlikely to give 6-ring fliers at 25 yards.

I'd look at several points:

Cheekpiece - does this fully support your head? Relying on your neck muscles is a quick way to a shifting group. Ideally you drop your head straight down and your cheek hooks over the edge of the cheekpiece.

Buttplate height: too high/low will see you straining to bring the sights onto the card, and is likely to tense your shoulder. With a hook there are additional complications; in a worst case scenario, it's acting as a lever to flip the muzzle. If you need a specific distance in height between the buttplate and cheekpiece for shoulder comfort, look at moving the handstop and sling to alter muzzle height.

Sling tension - is the sling pulling the butt properly into your shoulder, but without tensing your shoulder. Related to this, your jacket isn't slipping at all? This will drop the sling affecting tension, stability, recoil, relative head position amongst other things.

It sounds to me like the rifle doesn't quite fit, which is screwing with your sense of NPA.


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PostPosted: Fri Jan 19, 2018 6:47 am 
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Thanks, everybody, for your comments.
Ammunition is RWS Special Match, which should be capable of holding the spot at 25 yds, though I have once or twice had a loud round that went high.
The suggestion about cheek piece was helpful. I thought about what was happening, and realized that I am probably using a little muscular effort to align eye and sights. I've raised it 2mm, and will see how things go.
The whole butt position issue is something I'm unsure about. I do use a hook, because I thought that should make it easier to get a consistent position, by raising the butt until the hook stops it going any further. But I am not convinced that the top of the butt is always ending up in the same place on my jacket/shoulder.
I don't see any evidence of anything loose on the gun (it's barrel-clamped free action, not bedded).


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PostPosted: Fri Jan 19, 2018 7:05 am 
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Location: Taunton, Somerset
Jedin,

How do you seat the rifle in your shoulder? Lots of new shooters hold the grip, and lift it from there. Even with a hook, this doesn't work well. You'll get much more consistent fit if you tuck in the butt by hand. Once you have the sling connected, your right hand against the stop, and your right arm extended, take hold of the buttplate with your left hand. Put your thumb at the top of the plate. Now lift the butt up and swing it into your shoulder from the side. A side approach opens your shoulder and flattens the jacket. When you take your hand out and hold the grip, the shoulder and jacket fold around the butt, trapping it. Mounting the rifle like a shotgun lets it sit on top of the creases in the jacket.


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PostPosted: Fri Jan 19, 2018 9:28 am 
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Location: Cincinnati, OH
What power MEC lens are you using? And how old are you?

Vertical stringing is one of the symptoms of an underpowered land (and you are about 40 years old), where the eye begins to have difficulty focusing close, so the front sight is getting inconsistent focus.

You want to be using a lens with +0.50 diopters added to any distance vision prescription you have.

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PostPosted: Fri Jan 19, 2018 9:43 am 
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Thanks, Art, I'll check that. I'm 53, and my normal contact lens is -4.75 (and astigmatism correction) for distance vision in the left eye. My optician said she's had Olympic shooting clients, so I'd hope she knew to add something, but I will check!


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PostPosted: Sat Jan 20, 2018 5:32 am 
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Location: Taunton, Somerset
[quote="ShootingSight"Vertical stringing is one of the symptoms of an underpowered land (and you are about 40 years old), where the eye begins to have difficulty focusing close, so the front sight is getting inconsistent focus.[/quote]

Art,

Why would this cause specifically vertical errors? I understand that without appropriate correction, you won't get a clear and balanced sight picture. But I don't understand why the result would fall in only one direction; why not laterally, or diagonally?

Although Jedin doesn't mention his sights, it's almost certain he has an aperture foresight not a post. That has been the standard choice for British domestic prone shooting for decades.


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PostPosted: Sat Jan 20, 2018 9:45 am 
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Joined: Fri May 18, 2012 9:37 pm
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Location: Cincinnati, OH
Good point - that was a brain fart on my end. Vertical stringing due to bad eyesight is if you shoot with a post. It should not be a root cause if you are shooting with a front aperture.

Reason is that you are centering the bull left-right over the post, so even if the image is blurry, your brain can still judge symmetry. For elevation however, you only have one top edge, so you have to be able to see it. If the post gets blurry, it will look bigger/smaller, so it will impact elevation, but the symmetry is unchanges so windage error suffers a lot less.

The reason for the +0.50 added is that this has a focal point of 2 meters, which is the hyperfocal point for the front sight. What this means in photography is that if you focus at 2 meters, your eye's natural depth of field will range from 1 meter to infinity, so while the actual sharpness will depend on aperture size, the depth of field is centered between the front sight and the target.

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ShootingSight LLC
www.shootingsight.com
shootingsight@fioptics.com
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PostPosted: Sun Jan 21, 2018 12:35 am 
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Joined: Mon Jan 21, 2013 9:53 pm
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I found a little thing this week shooting my 1410 using a champions choice canvas jacket. There are a couple straps to tighten the shoulder and the clamp on tbe straps popped open and I didn't notice...... It allowed my shoulder mount to move fore and aft a tiny bit. I had a periodic big miss high or low and it was maddening. Tightened the strap and the shoulder mount point became more solid and the vertical movement disappeared. They were embarassing 4 and 5 ring shooting like youre drunk misses and they went away after resetting the shoulder straps.....


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PostPosted: Sun Jan 21, 2018 7:37 am 
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Joined: Mon Jan 03, 2011 11:33 am
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Location: Taunton, Somerset
spektr wrote:
I found a little thing this week shooting my 1410 using a champions choice canvas jacket. There are a couple straps to tighten the shoulder and the clamp on tbe straps popped open and I didn't notice...... It allowed my shoulder mount to move fore and aft a tiny bit. I had a periodic big miss high or low and it was maddening. Tightened the strap and the shoulder mount point became more solid and the vertical movement disappeared. They were embarassing 4 and 5 ring shooting like youre drunk misses and they went away after resetting the shoulder straps.....


IMO that's a common complaint with off-the-peg jackets; stiff canvas and a generous cut, mean yanking on the shoulder straps is necessary. However, I suspect the butt was a little loose, which exacerbated the problem. Even if the jacket isn't completely smooth and taut, the buttplate should press hard enough to stay still under sling tension -at least not to throw shots at the edge of the black.


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PostPosted: Wed Jan 24, 2018 12:30 pm 
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Location: Charleston, S.C.
A dirty bolt could be part of the problem plus are you getting solid firing pin hits? Check the spring tension. It might be time for a replacement. Try shooting the gun in a rest to see if it changes your groups.


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PostPosted: Wed Jan 24, 2018 12:35 pm 
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Joined: Thu Dec 08, 2016 10:10 am
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Thanks for further replies!
I do try to bring the butt into my shoulder in the standard way, but possibly I don't pay as much attention as I should. I concentrated on Monday, and had some bad cards, but nothing catastrophic.
I did move the hook a bit, so that it engages less strongly with my side .. that seemed to make it easier to keep the cant constant.
I don't think a dirty or weak bolt is very likely - it's only a year old, and I do check the bolt when I clean.


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PostPosted: Wed Jan 24, 2018 1:12 pm 
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Location: Taunton, Somerset
Jedin,

If the hook was a bit too tight against your ribs/armpit, this can cause funny shots. Effectively the hook stops the butt short of where you want it, and you push with your shoulder to get it in. It's possible to push down on the hook, flipping the muzzle up. Fitting the hook takes some trial and error, so it's common to need a little tweaking after the initial set up.

As for the bolt springs, the Anschutz techs have suggested these be replaced every few years; the 1800/1900 spring isn't that sturdy. I think it would take a lot of shooting to need replacement after a year:choosing to replace at this point is different, and given the low cost brings peace of mind for some.


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PostPosted: Wed Jan 24, 2018 5:36 pm 
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Location: Melbourne, Australia
I'm not saying your bolt is the cause, but have you disassembled it and cleaned it anyway? I clean mine as best as I can by spraying Balistol/wiping every time, but I fully disassemble it for cleaning after every thousand rounds or so, which at the moment is about every 4 weeks! They get pretty nasty in there, and grit etc.


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