The adjustable iris does make the little Williams sight look a lot bulkier, but for me the advantage is that in very bright light I can tune down to a smaller aperture and get a sharper sight picture. Open up in dim conditions to better see target and front sight.
What do you mean grommet? It is all metal and allows one to use the standard Gehmann iris which I think is a metric M9 thread in a Redfield/Parker Hale/Williams/Lyman sight which is 7/32"This is the adapter, just a simple grommet really. Any good shooting supply place should have it:
PH999 Thread adaptor for standard irises into Parker-Hale or Redfield | AABCE664F0D746C3B7694002816163C4
Adaptor for standard irises into Parker-Hale or Redfield Steel constructionwww.gehmann.com
As noted, Gehmann makes a version of the iris with the US / Parker-Hale thread built it. But the advantage of the adapter, of course, is that you can remove it and then use the same iris in any German sight, i.e., one iris will fit any sight you are ever likely to own.
The only disadvantage is that, if you get an iris with a magnifying lens, the smaller opening in US sights will narrow the field-of-view a bit. Still magnifies and focuses just fine, just a smaller picture. If no lens the adapter makes no diff.
I meant you saying the Williams aperture was too large. The hunting peep that generally comes with them and the twilight aperture are 0.093” opening. The target aperture is 0.050”.
Yes, it's steel and configured as you see in the pic - male US thread (7/32 - 40) on the front, female German thread (9.5 mm x 1.0 mm) in the back. Some sellers do refer to the gadget as a "grommet" though that does seem an odd use of the word. Somebody's bad translation from German maybe?
I know just what you are getting at but the finer adjustments on the diopter does make it more accurate for the kind of shooting that I do by having the finer adjustments. To do this card with a Williams I would probably have to aim off. If you are not a Diopter shooter the black sticky disks are big because the circle front forsight has to surround the disk leaving an even ring of white thin enough to judge when the sight is centered. this oddly does not mean the thinnest. Not meaning to talk down but Diopter shooting is a great offshoot of target shooting although I find it very tiring on my old eyes. I am sure most of you know this but some may not.
Shot with my HW77. A smaller rear diopter opening does not necessarily mean greater accuracy, that is more a function of the shooter. It will give a somewhat sharper sight picture. For non target work a much larger diopter will give a brighter sight picture. Some of the old timers, and I suppose you could call me one, will remove the smaller diopter from a Williams or Lyman sight for hunting and use that large 7/32 hole and find it to be quite accurate. Don't ask me to get into the finer points of the physics of focus but a small opening can acutally be used as a "lens" in photography, ie a pinhole camera. Back when I was nearsighted I could make a pinhole and hold it up and distant objects would focus, without using my prescription lenses. A larger opening would not tend to focus as finely. Back in my college ROTC days when shooting smallbore match using the double diopter system we were simply given rifles with Redfield international sights, no idea of the diopter size. I suspect now 60 years later if they had different diopter sizes for those of us with less than perfect vision we could have shot without our eyeglasses. I know that before my cataract surgery, I was slightly nearsighted, and could shoot very well without glasses using a small to med size diopter.I know just what you are getting at but the finer adjustments on the diopter does make it more accurate for the kind of shooting that I do by having the finer adjustments. To do this card with a Williams I would probably have to aim off. If you are not a Diopter shooter the black sticky disks are big because the circle front forsight has to surround the disk leaving an even ring of white thin enough to judge when the sight is centered. this oddly does not mean the thinnest. Not meaning to talk down but Diopter shooting is a great offshoot of target shooting although I find it very tiring on my old eyes. I am sure most of you know this but some may not.
