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FRONT IRIS

Posted: Mon Jun 21, 2010 3:59 pm
by orfanos3
i am new and i would like to make a question. what is the diameter that the experienced shooters prefer in the front shooting rifle?

Posted: Tue Jun 22, 2010 1:23 am
by bruce
The one that produces the smallest groups. :)

Foresight size varies a lot between shooters. Both in aperture diameter and ring thickness.
The choice is influenced by some variables. The distance between the rearsight and foresight being the major one.
Amongst the shooters that I know, there is a general tendency for the diameter to increase with age.

In my mid twenties, I used a 3.6mm Anschütz plastic aperture.
And now that I'm north of fifty, I use Centra High End inserts, 4.2mm in diameter, varying between 1mm, 1.1mm, and 1.2mm in ring thickness, depending on the conditions.

I've experimented with an extension tube, and therefore larger diameters, but the extra perceived movement lead to me hesitating on the trigger, and a decrease in performance, so I gave up on that after a year.

FRONT IRIS

Posted: Tue Jun 22, 2010 2:59 am
by orfanos3
3.3 3.4 is excessive?

Posted: Tue Jun 22, 2010 7:49 am
by tsokasn
orfanos3,where are you from?

Posted: Tue Jun 22, 2010 1:02 pm
by Rutty
3.3 3.4 is excessive?
On a standard length barrel they are on the small side. Broadly speaking, having a foresight that is too small is likely to be more disadvantageous than having one that is too big.

3.8 is probably not a bad starting point.

Bruce mentioned ring thickness, remember that this has an effect on the apparent foresight diameter. A thick ring will make the aperture appear small and vice versa and it's the ring that you must focus on.

Hope that this helps and not merely serves to further confuse.

Rutty

Re: FRONT IRIS

Posted: Tue Jun 22, 2010 1:09 pm
by bruce
orfanos3 wrote:3.3 3.4 is excessive?

I can't see through your eyes :)

But,
on an Anschütz 690mm barrel, for example, I'd expect apertures of that size would result in a sight picture where there would be almost no gap between the aiming mark and the foresight ring.

So, 3.3-3.4 is probably at the very limit of what can be used.

In my experience anyway :)

Posted: Tue Jun 22, 2010 6:25 pm
by scott75
At the moment I am using a 3.6. I was using a 4.0 but was playing one day and used from 3.0 up to 4.2 and I found that I had the best sight picture using the 3.6. I found that any smaller was a real challenge to have a consistant sight picture, as the gap between the black of the target and the front element was just to fine to be able to use properly. As a by product I found that my eyes were really straining to cope with the smaller elements.

Well thats my 2 cents worth!!

Happy shooting

Cheers Scott

Posted: Tue Jun 22, 2010 9:31 pm
by BartP
Orfanos,

What it comes down to is that you need to be prepared to use a variety of sizes. Being a great iron sight shooter demands that you be able to switch out your iris for one that meets the light conditions of the match you are shooting. Everyone has a different idea about what the perfect sight picture is. No one here can tell you what is best for YOU.

Most of us use a 25-27" barrel as a rule. Adding a 10" tube gives you roughly a 40" sight radius. This will require you to navigate somewhere between 3.9 and 4.5 depending on your shot process, hold, eyesight clarity, and "feel". A good start is allowing the bull to fill 2/3 to 3/4 of the aperture. Experimentation is the key. If you have trouble seeing a clear bull one morning as the sun burns off the early dew - try increasing the diameter a couple of tenths and see if it helps. This will illustrate the necessity of being able to interchange your aperture size.

Bartp

FRONT IRIS

Posted: Wed Jun 23, 2010 2:43 am
by orfanos
thanks a lot..i see in practice

Posted: Wed Jun 23, 2010 10:16 am
by Guest
as a general rule of thumb, it is mentioned in MEC's book Ways of the Rifle as well, the amount of white between the bull and the inner edge of the ring should be roughly the same thickness as the ring itself.

Posted: Sat Jul 03, 2010 8:33 pm
by weilers
Personally, I use 3.0 and 3.2 irises, depending on condition. I like a thin (1.0) ring and a really tight sight picture. I'll get some flack for that, but that's my choice.

The only thing I can tell you is that it's your gun, it's your sight picture. Remember, everything we all do on this website is about one goal: hitting the 10-ring. How you do it is your business.

Best of luck to you.

Posted: Sat Jul 03, 2010 8:34 pm
by weilers
Personally, I use 3.0 and 3.2 irises, depending on condition. I like a thin (1.0) ring and a really tight sight picture. I'll get some flack for that, but that's my choice.

The only thing I can tell you is that it's your gun, it's your sight picture. Remember, everything we all do on this website is about one goal: hitting the 10-ring. How you do it is your business.

Best of luck to you.

Re: FRONT IRIS

Posted: Sun Jul 04, 2010 3:00 pm
by Guest
orfanos3 wrote:i am new and i would like to make a question. what is the diameter that the experienced shooters prefer in the front shooting rifle?
The answer is, "it depends".

Are you shooting air rifle or smallbore? It makes a difference because the air rifle target appears "larger" than a smallbore target.

What is the distance from your rear sight to your front sight? The further the front sight is from your eye, the larger the aperature needs to be.

Are you shooting prone only? Most shooters will use different sized apperatures for prone, standing and kneeling.

If you provide additional information, we might be able to provide better suggestions.

FROND IRIS

Posted: Wed Jul 07, 2010 5:59 am
by orfanos3
I'm talking about air gun

Posted: Wed Jul 07, 2010 1:05 pm
by tsokasn
Air rifle,standing position.
In my case,the more stable the holding is,I tend to close the ring.

Posted: Wed Jul 07, 2010 9:55 pm
by gtrisdale
For standing air rifle, I would recommend 3.8 to 4.2. You can try different sizes in this range and see what seems to work best for you.