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rear sight for smallbore rifle

Posted: Tue Oct 05, 2010 9:53 pm
by infantrytrophy
Is a rear sight with 1/4 MOA clicks adequate for smallbore prone shooting?

According to Ancshutz, one click with the 7020/20 rear sight will move the point of impact 0.3mm at 15 meters (49.2 feet). This extrapolates to .072 inch (1.82 mm) at 100 yards. This is a great sight, but each click results in a very small movement of the point of impact.

A rear sight with 1/4 MOA clicks would move the point of impact approximately 0.25 inch (6.35mm) at 100 yards or .041 inch (1.04 mm) at 50 feet.

Is this 1/4 MOA sight adequate for smallbore prone shooting at 50 feet and 50 and 100 yards?

Posted: Wed Oct 06, 2010 12:00 am
by 1813benny
1/4 min adjustments are fine for conventional prone, but a little on the course side for international targets.

If using a standard length barrel (no extension tube), they will work fine for a beginner to intermediate hold. Once at the expert / master level, a finer level of adjustment 1/6 or 1/8 is an advantage with the better ability to hold.

The newer sights with 1/10th min (or more) adjustments are a waste of money. The simple reason is that the adjustments are finer than the grouping ability of the ammunition, resulting in only having to click more, which can become a real headache in tough wind conditions.

Posted: Wed Oct 06, 2010 8:33 am
by Barney
Anschutz 10 click = 1/4 and 20 click = 1/8

Posted: Thu Oct 07, 2010 3:59 pm
by Roodaddy600
Barney, your math is off. The anschutz 10 clicks are not 1/4 minute clicks. They are finer than that. They are around 1/5 minute to 1/6 minute clicks

Posted: Sat Oct 09, 2010 9:28 am
by 1813benny
Pretty simple that the 10 click and 1/4 min are NOT the same...with the anschutz "10 click" sights, you have to move about 96 clicks up for 100 yards. For 1/4 min, you move about 24 clicks.

Posted: Sat Oct 09, 2010 6:02 pm
by KennyB
I believe that the Anschutz 10 click sights (certainly the old "International" sights) are/were 1/6 MOA and that with these, the come up from 25yds to 50 was 13-14 clicks and the come up from 50 to 100yds was 40 clicks.

I've just started using a 20 click 7020 -which would be 1/12 MOA - and I like it a lot. With my 6805 sights I found I was adjusting between clicks (and I use a tube too...).
Maybe you just get what you pay for.

I'm not sure what Benny means by "the adjustments are finer than the grouping ability of the ammunition"...... but you do end up doing a lot more clicking - twice as much in fact.

K.

Posted: Sat Oct 09, 2010 8:22 pm
by Soupy44
Benny is just saying the 20 click sights may be a touch too fine for some people, or, that at some point, clicks get too fine. What would the point be to have sights that take 100 clicks to go from one side of the 10 ring to the other. 100 may be excessively excessive, but I think part of Benny's point is how much is too much?

Posted: Sun Oct 10, 2010 6:23 am
by Guest
There needs to be a correlation between the adjustment at the sight and the location of the shot on the target. If the movement of each click is less than the inherent variability of any particular brand of ammo/barrel combination, then there would be little correlation. A click or two (or more) may have no validity. The same would be true, for example, if your hold varied from from one side of a ring to the other side.

Dennis

Posted: Sun Oct 10, 2010 2:50 pm
by KennyB
I may be wrong but here's how I see it:

Lets say that the bull is 1 MOA (approx).

if you have ammunition or hold (or combination of the two) that barely holds the bull, you need to be able to center the group exactly in the middle in order to shoot all tens.
If your sight only gives you 4 or 5 points within the bull* (i.e. is 1/4 MOA) there is a very good chance that you will shoot some nines as the center of group will most likely be slightly left or right or high or low.

However, if you are blessed with good ammunition and a good hold and can achieve groups that are significantly smaller than the bull, you could probably get away with a 1/4 MOA sight and still shoot all tens.
Those who are so blessed are probably looking to shoot as many 10.9's or X's as possible and so will be using sights with finer adjustment anyway to maximize their scores.

100 clicks/MOA is a bit over the top but 12 clicks/MOA doesn't seem unreasonable to me.

K.



* If you're very lucky you'd get "center, 50% left/right, edge left/right" - at worst you'd get "25% left/right, 75% left/right"

Rear Sight

Posted: Thu Oct 14, 2010 9:51 am
by dege41
Look at this sight 1/8 min.

hpsight.com