# Sight accuracy (elevation backlash)



## AngelRa (Nov 15, 2010)

I have 3 sights.
Sure Loc Edge
Sure Loc Challenger
Shibuya Ultima CPX

Just for curiosity, I put together a fixture to measure the travel of the sights. I wanted to know the amount of backlash (the difference or error when adjusting *up* versus adjusting *down*). To test the sight is adjusted up until the fixture dial indicates 0.000, noted the knob position, then I continue half a turn on the sight knob then turn back to the place where it was previously 0.000 and note the error.

The Sure Loc Challenger has a backlash of 0.0015" to 0.0020"
The Sure Loc Edge did 0.0010"
The Shibuya Ultima CPX did around 0.0002"

I am thinking that to make the Sure Loc sights work I will have to always adjust going up. Is that too extreme?

I would like to know how do you fine adjust your sight when shooting long distance?
Is one or two clicks error too much?


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## zenarch (Aug 3, 2002)

AngelRa said:


> I have 3 sights.
> Sure Loc Edge
> Sure Loc Challenger
> Shibuya Ultima CPX
> ...


Are you sure the decimal points in your results are right??? 1 or 2 thousanths of an inch on the Sure Loc sights would be darn good, I would think. On the Shibuya only 2/10 of a thousanth is hardly measurable. If I'm not mistaken one complete turn of an 8 click sight move it .032", which would mean 1 click would be .004", which might mean something only to the very best archers.
Joe B.


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## OBE (Dec 4, 2009)

Would you mind retaking those exact tests? This time when you return back to the zero position, go past zero one click and then move back up to zero. I am curious to see if the error improves. Thanks.


AngelRa said:


> I have 3 sights.
> Sure Loc Edge
> Sure Loc Challenger
> Shibuya Ultima CPX
> ...


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## AngelRa (Nov 15, 2010)

I did that but instead of one over I did 4 over then return to 0 and found no error.

Computed the significance of the 0.002 error. At 80 Yards is around 0.17 of an inch which is quite small.

Also, I measured a Sure Loc Supreme and it was the same 0.002"

In my opinion this backlash error is small enough to be *negligible* (and if a 0.17" is relevant, it is easily cancelled by just going over a couple of clicks then return to the desired place so the final adjustment is always going up).


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## OBE (Dec 4, 2009)

Thanks for the feedback.


AngelRa said:


> I did that but instead of one over I did 4 over then return to 0 and found no error.
> 
> Computed the significance of the 0.002 error. At 80 Yards is around 0.17 of an inch which is quite small.
> 
> ...


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## rossing6 (Jun 7, 2008)

Anytime you adjust a sight, always come up to the number you are going for-or down, keeping any slop in the same direction...helps with the consistency if that is a problem. Have shot some very loose sights and was still very accurate out to 101 yds, so I'd not be too concerned with it. IMHO


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