some advice please

[Richard144]

I am the proud owner of an Anschutz 1907 with a very nice walnut stock that I bought a few years ago from a friend. It came with the more expensive sight set and adjustable apertures both front and rear. I have been shooting it with some success and pleasure but I have never been sure of the correct way to adjust the apertures or exactly what the methodology is. Could some knowledgeable person please respond with a short primer on the subject.
it would be much appreciated. Thanks.
Rick b.

[Tim S]

Rick,

There are a few "Aperture sight 101" threads on the forum:

http://targettalk.org/viewtopic.php?t=63038

http://targettalk.org/viewtopic.php?t=63145

When you you say that you're unsure of how to adjust the apertures, do you mean adjusting Point of Impact (POI) to coincide with Point of Aim (POA)? Or do you want to know how to vary the size of the holes in the rearsight and foresight?

For 1: all adjustment for POI is done at the rearsight. The turret at the top of the sight controls elevation, vertical POI. The turret at the side controls windage/azimuth (horizontal POI). Shoot a group at your chosen distance. Note the distance from the centre of your group (not the nearest edge) to your point of aim, that's normally the centre of the target. Turn the turrets to compensate. Most Anschutz sights adjust 1/6 minutes of angle per click; this means 6 clicks move the POI by 1in at 100 yards. At 50 yards 6 clicks moves POI .5in (12 clicks move 1in). Some have finer clicks; roughly 12 per 1in at 100yds, and 24 per 1in at 50.

For 2: To adjust your field of view through the rearsight you need to move the rearsight: closer to your eye for a larger hole, and further away for a smaller hole. This is your eye relief. Eye Relief also has an effect on how clearly you see the foresight and target, as well as the brightness. Your adjustable aperture lets you control the brightness without moving the whole sight. The numbers around the eyepiece are the size if the aperture in millimetres: 1.0-1.2mm is a good starting point. You might go a little smaller on a very bright day, but not too much smaller of the sight picture will be very dark. On a dark indoor range, you might go a bit larger to let in more light.

The size of the foresight element can make a big difference to your shooting. For typical smallbore targets (ISSF/NSRA/NRA) 3.4-3.6mm would be the minimum I'd recommend. That's for prone, where your hold is steadiest. For standing, you'd want a larger aperture, so the target doesn't touch the inside as you aim; say 4.0mm+. Even in prone, you want a good bright gap around the target. A brighter gap helps you aim; your brain sees light contrast better than size, so if the target is off-centre the gap is brighter opposite.

[ChickenChowda]

I second Tim's advice, In addition front aperture size largely depends on barrel length. the longer sight radius the larger aperture required usually. I shoot 50 foot indoor (Ncaa) and I have a very large sight radius. I use a 4.8 because of this but have used as large as a 5.2. For air rifle in general 4.0 Is average, and probably about the same for a standard small-bore gun with no tube. This would be a good starting point to go up from Its usually better to error on the larger side than the smaller side, Too small of an aperture can cause some weird light refraction issues that are far beyond my paygrade to fully understand.

[Richard144]

thank you for your responses. I have a better idea of what I should be doing already.
Rick

[Scott J]

Might read this article>>>http://www.usashooting.org/library/Inst ... b_2011.pdf
There are some recommendations at the end.

Scott

[Richard144]

Scott,
That was a great article. Once again things are counter intuitive and not what one would think. Big help.
Rick