TargetTalk

How do you determine the correct front Aperture Sight insert size?
Is there a formula to determine the correct size?
The smallest aperture in my set is 3.2 and it seems much too large.
My daughter is shooting a CZ 452 Scout. It is a small rifle that the Eye-to-Front Sight distance is only 24” inches.
She is Shooting A17 NRA targets at 50 Feet.

Thanks for the help

I was taught that it is the sight picture.
look thru the sights at the target and see the size of the bull in relation to the front aperture.
#1 - front sight should be large enough that the bull remains INSIDE the aperture "most" of the time, as your wobble moves the rifle about.
#2 - as your hold changes from day to day, steady to wobbly, change/adjust the size of the aperture so #1 above is followed
#3 - as your hold gets more steady, go to smaller apertures to maintain #1 above
#4 - do not go so small that there is just a "sliver" of light around the bull, that makes the eye strain too much. I will not reach this point of steadiness so I don't have to worry about this one.

I'd be inclinded to have the aperture big enough so that the bull essentially never drops out (prone). In standing, maybe accept a bit more. As Gary mentions going too small will make it much more difficult so err on the larger size and then come down slighty.

Rob.

What do you mean by dropping out(prone) Rob, as my foresight's always moving off the target as I breath, until I'm ready to release the shot then I'm stationary on the target

Colin wrote:What do you mean by dropping out(prone) Rob, as my foresight's always moving off the target as I breath, until I'm ready to release the shot then I'm stationary on the target

We're not talking about where the sights move to when breathing we were talking about movement within the hold, i.e. when on target. So you'll be holding your breath prior to releasing the shot for 3 - 5 seconds (ish) and it's in that period that your sights will 'wobble' - it's that wobble that I'm saying the bull should not be moving outside of the foresight. For me the visual image isn't a million miles away from (0) , with the '0' being the bull, and the ( ) the foresight aperture.

Rob.

There is an excellent article about this, including a chart for eye to front sight radius for various targets, in the second to last USA Shooting News magazine. You may be able to get a copy from USA Shooting (mine is lent out right now or I'd look it up for you).

RobStubbs wrote:

Colin wrote:What do you mean by dropping out(prone) Rob, as my foresight's always moving off the target as I breath, until I'm ready to release the shot then I'm stationary on the target

We're not talking about where the sights move to when breathing we were talking about movement within the hold, i.e. when on target. So you'll be holding your breath prior to releasing the shot for 3 - 5 seconds (ish) and it's in that period that your sights will 'wobble' - it's that wobble that I'm saying the bull should not be moving outside of the foresight. For me the visual image isn't a million miles away from (0) , with the '0' being the bull, and the ( ) the foresight aperture.

Rob.

ok,I see what you mean, but I don't wobble that much when on hold, especially in prone,ok there is movement there but never off the target as such that's what confused me
I don't so much hold my breath but breath out when coming onto the target,then pause to check sight picture/flags then release
the shoot, as you say normally before max 5 seconds
Standing just lately probably better to just take the element out and use the foresight

Colin wrote:ok,I see what you mean, but I don't wobble that much when on hold, especially in prone,ok there is movement there but never off the target as such that's what confused me
I don't so much hold my breath but breath out when coming onto the target,then pause to check sight picture/flags then release
the shoot, as you say normally before max 5 seconds
Standing just lately probably better to just take the element out and use the foresight

Colin,
That's fine but remember the OP asked the question re his young daughter, who may well have more 'wobble' than a more seasoned shooter.

As an minor aside, I use a variable foresight element now, which makes trying different aperture sizes an awful lot easier. Thus far though I've stuck at 3.7mm, although I did try 3.8, but just briefly. And may experiment more methodically when I have sufficient free time.

Rob.

Rob.

The January/February issue of USA Shooting News has a chart on page 8, for "minimum" aperture sizes. Unfortunately is only goes down to 28" of eye-to-front sight radius. For A17 target at 28" it shows minimum of 3.0 ( with 3.1 at 29" and 3.2 at 30").

Using this as a guide you MIGHT try as small as 2.6 diameter at 24", but try a 2.8 also.

Hope this helps.

Thanks for all the help.
She settled in with a 2.7 and shot well.
Her scores were 427 out of 500 on A17 Targets in practice at our range, and a 389 in competition last weekend in Grand Junction, great for an eight year old, in a new range.