What is this adjustable iris sight ?
Sounds very interesting to me.....
Oh man, I was afraid someone was going to ask a question like that.
Mind you, it was somewhat over 20 years ago that I made this setup and the details are a bit fuzzy. I mean, that was about half my life ago....
I don't remember where I got it (special ordered through a local gunshop, I think, maybe the Shotgun News) but HK-91s were a kind of hot item back then and actually affordable. I bought lots of goodies - the overpriced, bulky scope mount, the overpriced, bulky bipod, the ejection port anti-mangling brass buffer, and various other overpriced stuff for it. As I recall, the sight was around a hundred bucks - but what wasn't for the HK-91?
It was disc-shaped and about the size of something between a nickel and a quarter, I think. Picture a small doughnut with an adjustable iris in the center. It had a small lever on the top or side that controlled the iris aperture. You just moved it from one side to the other to adjust it. You could open it quite wide or close it down to completely blocked or anywhere in between. Infinitely adjustable with no clicks or anything throughout its range of movement.
For quick target acquisition it opened up pretty wide and for long distance precision you could set it down to a very fine pinpoint. Quick to operate and very rugged. A little on the large side but not so much as to be of any consequence.
I believe it was made for HK's .308 machine guns and meant to be used when fired from a bipod. It would have excelled in that capacity, I think.
Now I'm curious again about exactly what it was I owned and am going to do some research. Whatever (if?) I come up with, I'll post it here in case anybody else is interested.
I personally felt it was a vast improvement over the standard HK-91 sight.