Today I was out shooting, and was having some problems. I shot (prone)all 9s, or better at 50 yards on an NRA target. However, my groups weren't very tight, and their centers didn't seem very consistent. First group of 5 i could tell that I threw several of them. The last 4 groups of 5 each felt better, but scoring wasn't much better. My friend said that he thought I was possibly messing up my breathing, or moving my head. I did notice that I was having a really hard time focusing my front sight. I could see the black bull ok, fuzzy but round. However, the hole in the front apeture didn't seem to be staying round, like it was elongating vertically, and the ring was kinda stretching towards 2 and 8 oclock.
Is it possible that my erratic grouping was a result of the front sight focusing problems? If so, what can I do about it? Do I need a new prescription for my glasses? I haven't had a pair in probably 5 years, although there wasn't much change last time I was checked. This was mid/late afternoon, and the sun was from maybe 5 oclock, with the target at 12. Maybe too much light coming from the target? I also notice that it seems to take me a while of looking through the sights before I take a shot, although I do shoot both eyes open.
Equipment is an Anschutz 1413 in a 1813 stock, 1970s vintage Anschutz rear sight, plane screw in rear peep w/blinder. Front is a 1970s vintage globe, with a Gehmann adjustable apeture. I usually keep the apeture fairly small, should it be larger? Should I be looking to change anything in my setup? I'm still muddling my way through this whole smallbore prone thing on my own, got back into shooting and with my first Anschutz 3 years back after graduating college. For reference, I usually shoot about 190/200 or so on a NRA A 23/5.
I have a 1613 with a fine crosshair Nikon 6.5-20, should I try that to see if it's my hold, or my eyes?
Sight focusing issues?
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Invictus87
- Posts: 24
- Joined: Sat Mar 30, 2013 8:10 pm
- Location: Southern Maine
Yes, it could be that you need glasses. But there could also be other issues. Tiredness, and dehydration can both impair vision when shooting with aperture sights. Taking breaks and drinking plenty of fluids will help.
As for too much light, yes this can affect your aim. Do you wear a hat? A cap or floppy brimmed hat will shade the sights and your eye.
Back to your eyes, if you are over 40 years old, then it's probable that glasses will help you see better and so aim better. A good optician/opthalmologist can make a lens that makes the foresight crisp and sharp, and the target as visible as possible. However not all opticians know what is required for shooting, and some think that good long distance vision to see the target is enough. In fact you want your eye to be focused a few feet ahead of the foresight; I have glasses just for shooting, the prescription for my aiming eye is +0.5 over my normal prescription to get the focus right. I recently had a check-up and got a new prescription, the difference (just 0.5 dioptres) was noticeable, I could actually see the foresight properly again!
From your description of the foresight turning oval, I wonder whether you have an astigmatism. Again this can be compensated for with a lens.
As for aperture sizes, you can't adjust the rear aperture, but have you made sure the eye relief is right for you? This is a very basic thing, but some folks are never taught about it.
Regarding the foresight, larger is better within reason. If the ring is too small you can ahve aiming errors but not see them. This happens because the inside edge of the aperture doesn't appear as a nice crisp edge, light is refracted from the edge so it is slightly fuzzy to look at. If the aperture is too small, you can overlap it with the target, but still see light around the inner edge of the ring. So the aperture should be big enough to contain the target no matter how wobbly your aim is. In Britain beginners are recommeded a 3.6-4.0mm aperture (standard 26-27in barrel). Below 3.4mm is too small, unlesss you have an exceptionally good hold (think Olympic level), or shoot from a bench.
Tim
As for too much light, yes this can affect your aim. Do you wear a hat? A cap or floppy brimmed hat will shade the sights and your eye.
Back to your eyes, if you are over 40 years old, then it's probable that glasses will help you see better and so aim better. A good optician/opthalmologist can make a lens that makes the foresight crisp and sharp, and the target as visible as possible. However not all opticians know what is required for shooting, and some think that good long distance vision to see the target is enough. In fact you want your eye to be focused a few feet ahead of the foresight; I have glasses just for shooting, the prescription for my aiming eye is +0.5 over my normal prescription to get the focus right. I recently had a check-up and got a new prescription, the difference (just 0.5 dioptres) was noticeable, I could actually see the foresight properly again!
From your description of the foresight turning oval, I wonder whether you have an astigmatism. Again this can be compensated for with a lens.
As for aperture sizes, you can't adjust the rear aperture, but have you made sure the eye relief is right for you? This is a very basic thing, but some folks are never taught about it.
Regarding the foresight, larger is better within reason. If the ring is too small you can ahve aiming errors but not see them. This happens because the inside edge of the aperture doesn't appear as a nice crisp edge, light is refracted from the edge so it is slightly fuzzy to look at. If the aperture is too small, you can overlap it with the target, but still see light around the inner edge of the ring. So the aperture should be big enough to contain the target no matter how wobbly your aim is. In Britain beginners are recommeded a 3.6-4.0mm aperture (standard 26-27in barrel). Below 3.4mm is too small, unlesss you have an exceptionally good hold (think Olympic level), or shoot from a bench.
Tim
As has been mentioned you may need some eyesight correction. I recently got a custom shooting glasses lens with astigmatism correction for my daughter. Your local eye dr should be able to take care of it.
Everyone likes to say their rifle shoots tiny groups inside the 10.5, very, very few do. Mount up a good scope with parallax adjustment. Shoot it from a bench. Compare your groups. It may be your rifle as much as your sighting issues.
Everyone likes to say their rifle shoots tiny groups inside the 10.5, very, very few do. Mount up a good scope with parallax adjustment. Shoot it from a bench. Compare your groups. It may be your rifle as much as your sighting issues.
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Invictus87
- Posts: 24
- Joined: Sat Mar 30, 2013 8:10 pm
- Location: Southern Maine
Thanks for the replies. It's possible that I was tired and/or dehydrated. I had just gotten of an 8hr OT shift at work (machine shop). This isn't a problem that I always have, so hopefully it's not astigmatism, as I'm 25.
Should I get an adjustable rear apeture? I really don't know how to make sure the relief is set correctly. Like I said, I'm muddling my way through this all the best I can, by experimenting and reading online.
I'm pretty sure that my front apeture is large enough that there is light all the way around the bull, and not overlapping it. I just pulled it out, and checked the size, looks like it was set at 3.5. I'll open it up next time I go out.
I have shot this rifle off the bench with a scope when I first got it, and it was shooting 1 hole for 5 shots at 50 yards. However, that was with the old 1413 stock, haven't tried it with a scope since I put it in the 1813 stock.
Should I get an adjustable rear apeture? I really don't know how to make sure the relief is set correctly. Like I said, I'm muddling my way through this all the best I can, by experimenting and reading online.
I'm pretty sure that my front apeture is large enough that there is light all the way around the bull, and not overlapping it. I just pulled it out, and checked the size, looks like it was set at 3.5. I'll open it up next time I go out.
I have shot this rifle off the bench with a scope when I first got it, and it was shooting 1 hole for 5 shots at 50 yards. However, that was with the old 1413 stock, haven't tried it with a scope since I put it in the 1813 stock.
After an eight hour shift, it's likely that your eyes will be tired, along with the rest of you. I find that lots of computer work (I'm office based) does not help my shooting.
As for an astigmatism, this is not an age related condition. I first found I had an astigmatism in my right eye at 19, but I didn't need any correction for more than 10 years. An appointment with a optician is worthwhile, even for peace of mind if you get an all clear. Do explain what you want before you book, and maybe take your sights with you.
An adjustable rear aperture is useful, although not essential. I personally feel an adjustable rear is more useful than adjustable front, but others may disagree. Strictly speaking you don't use an adjustable rear aperture to set the eye relief. This is simply the distance from your eye to the aperture; it varies from shooter to shooter, but is normally 1-2in. Eye relief governs the depth of focus: the further the rearsight is from your eye, the longer and narrower your focus becomes, which makes the foresight clearer. The downside is a much reduced view down range. I shoot with quite a long eye relief, but I can't see many wind flags; if I decrease eye relief to widen my view, my groups open up, although the sight picture looks good.
What an adjustable rear iris does is to allow you to vary how bright the sight picture is. Outdoors light levels change, so you can adjust the iris to keep the perceived brightness constant. With a fixed aperture, the only way is to physically move the rearsight, which is not a good idea mid-string.
A 3.5mm foresight is just OK, but it won't hurt to try a little larger you'll never know what the optimum size is unless you experiment. Many shooters will change the aperture size/thickness to control the sight picture in changing light conditions.
As for an astigmatism, this is not an age related condition. I first found I had an astigmatism in my right eye at 19, but I didn't need any correction for more than 10 years. An appointment with a optician is worthwhile, even for peace of mind if you get an all clear. Do explain what you want before you book, and maybe take your sights with you.
An adjustable rear aperture is useful, although not essential. I personally feel an adjustable rear is more useful than adjustable front, but others may disagree. Strictly speaking you don't use an adjustable rear aperture to set the eye relief. This is simply the distance from your eye to the aperture; it varies from shooter to shooter, but is normally 1-2in. Eye relief governs the depth of focus: the further the rearsight is from your eye, the longer and narrower your focus becomes, which makes the foresight clearer. The downside is a much reduced view down range. I shoot with quite a long eye relief, but I can't see many wind flags; if I decrease eye relief to widen my view, my groups open up, although the sight picture looks good.
What an adjustable rear iris does is to allow you to vary how bright the sight picture is. Outdoors light levels change, so you can adjust the iris to keep the perceived brightness constant. With a fixed aperture, the only way is to physically move the rearsight, which is not a good idea mid-string.
A 3.5mm foresight is just OK, but it won't hurt to try a little larger you'll never know what the optimum size is unless you experiment. Many shooters will change the aperture size/thickness to control the sight picture in changing light conditions.
Last edited by Tim S on Mon Apr 01, 2013 3:12 am, edited 1 time in total.