Eagle eye in competition?

[aquarius11]

Hi peeps
I have just bought a magnification ring (.75 eagle eye) for my foresight as i was under the impression i can use this to improve my vision of the target but i have been told i cant use it in competition, can anyone help and give a finite answer?
thanks in advance
aquarius11

[bullbarrel]

You don't mention what competition and at what level.

Go on, give us a hint.

If NSRA then its mentioned in the 2009 rule change.


If NRA then:
The actual text of the relevant rules from the Bisley Bible is set out below. The provisions can be summarised as follows:

• A prescription corrective lens is allowed, either worn by the shooter (in everyday glasses or special shooting spectacles) or mounted in/on the rearsight.
• A dioptre can be fitted to the rearsight.
• An Eagle Eye is allowed in the foresight but NOT in conjunction with magnification in the rearsight; however, it can be used in conjunction with a prescription lens.

Why not get an online version of the rules for the comp you are entering and have a look for yourself?

[aquarius11]

OK its a .22 prone 25yds county league.
Many thanks for the reply Bull.

[hwtyger]

Matches ruled by international ISSF rules, those are nót allowed (except maybe in rested senior class I dunno)

[Speedystcks]

Hi,

I just purchased a Gehmaan 575 rear sight last week with magnifyer, 6 colour lense & 2 polariser light adjustment.

Having just attended a training weekend at DSTGB @ Stoke Mandeville I was told it could only be used in NSRA competitions and could not be used in any ISSF competition.

I have MS and fell over in August tearing my retina and leaving me with a slight detachment of the optic nerve - just wonderful, I purchase a corrective rear sight only to be told it is technically illegal!!

DSTGB committee members later informed me a prescription lense fitted inside shooting glasse was only permitted.

So if you are like me only looking to use the lense for club use then fine but if you want to shoot at the highest level then NO.

If you look on the ISSF rule book you can verify these details and likewise the NSRA rule book who allow such sights.

Like me you probably feel you've wasted a load of money!

In retrospect I should have bought a replacement lense for my shooting glasses.

I hope this comment is of use as I'm pretty sure other readers will verify my comment.

Regards
Speedystcks.

[tim s]

OK its a .22 prone 25yds county league.
Many thanks for the reply Bull.

NSRA rules allow eagles eyes for .22 prone, but not with a Gehmann-type magnifying rearsight lens. You can use just the eagle eye, or eagle eye + glasses, or an eagle eye + fixed lens and with w/o filters.

However an eagle eye isn't magic. It's a low power lens that makes the target look larger; it won't make the target look less blurred (it may even make it worse) because it's too far from your eye. If you want a good sight picture that doesn't strain your eye, you need a lens at the back. Typically your distance prescription + 0.50 does the trick; this puts the focus ahead of the foresight, so it's still sharp, but makes the target less blurry. It's worth seeing a good optician that understands aperture sights, to get an exact prescription.

[aquarius11]

Very informative, many thanks
aquarius11

[NTSOG]

Hi Folks,

Tim S wrote: "Typically your distance prescription + 0.50 does the trick; this puts the focus ahead of the foresight, so it's still sharp, but makes the target less blurry." Could you explain this in more detail Tim? I recently tried a Gehmann lense fitting set just rearwards of the peep sight on my Walther LG90 with just my distance vision prescription. However the results were not significantly better than when I aimed just wearing my bi-focals. Why is the +.50 necessary? Does that change give the best of both worlds, i.e. points of focus?

Jim

Garibaldi, Victoria, Australia

[tim s]

Hi Folks,

Tim S wrote: "Typically your distance prescription + 0.50 does the trick; this puts the focus ahead of the foresight, so it's still sharp, but makes the target less blurry." Could you explain this in more detail Tim? I recently tried a Gehmann lense fitting set just rearwards of the peep sight on my Walther LG90 with just my distance vision prescription. However the results were not significantly better than when I aimed just wearing my bi-focals. Why is the +.50 necessary? Does that change give the best of both worlds, i.e. points of focus?

Jim

Garibaldi, Victoria, Australia

Jim,

Shooting with aperture sights is all about depth of field. The rear apertute compresses and extends your focal lenth so the foresight and target are almost in focus together, but you can't do both so conventional wisdom is to focus on the foresight because that moves but the target doesn't.

The idea of a +0.50 lens is to focus your eye at the hyperfocal length of the foresight so the target is clearer, and your eye muscles aren't strained by maintaining a fixed focus. The +0.50 comes about because that works with a typical rifle barrel. The .50 has to be added to your distance prescription if ordering a simple lens; my distance prescription is +1.0 so mr shootibg lens is +1.50. With a Gehmann diopte you have to adjust it until clear. If it's an older lens it may be grubby, these are difficult to clean, and won't correct for astigmatism.

[NTSOG]

Hi Tim,

Thank you for your explanation. The lense I had made was optically correct for me [including my astigmatism], but I obviously need to get the optometrist to add that 0.50 to the lense made for shooting.

I look forward to trying the arrangement - the eye strain caused by trying to focus through the "normal" lense is quite tiring.

Jim

[tim s]

Jim,

Many good opticians think that the effect of the aperture is enough and good distance vision is all that's needed. I started with a straight .5 lens years ago, before I wore glasses everyday, and that helped.