It's different for every shooter, as all our eyes are in different levels of sight. Obviously most wont want a very small .040" for hunting, but how much larger depends on the shooter, and how far away the game will be.

If you have experience and success with the aperture, why not take a little extra time to get better shot placement?

I dug around in my “sight” toolbox drawer and what did I find? I found an aperture with a .122 dia hole ! It looks about right but I’ll also try with an aperture at all and compare. As I get older, I can’t remember much. I have been doing research on aperture sizes and all the while, I already had what I needed right under my nose.

Some 60 years ago I began hunting deer with a 93 Mauser 7x57 with a Marbles receiver sight.  My dad had me shoot with the aperture in for target practice then we removed it entirely for hunting.  I still use that format today on sights that allow me to.  Your eye pretty much automatically center in the large opening and allow a much wider field of view.  Tom

Practice before hunting is always a good idea, but as I noted, and Bulseyetom repeated, the eye naturally seeks the center of a circle regardless of size. More precisely, as in target work, with a much smaller diameter aperture. We are talking about "hopefully" ranges appropriate for hunting with receiver sights.

well, now that we have collectively solved welldone's quandary, we can allow him to make up his own mind!!

When in need of apertures, don't look any further than Apertures-N-More. They have every aperture known to mankind, or they'll make a custom one for you - and their prices are dirt cheap.

I don't care for "ghost rings". With my eyes they turn into "no rings", and I like at least some definition of a ring no matter how big the aperture hole. To that end I've acquired a few Merit adjustable iris apertures over the years. Depending on the model some of them open up quite wide, at the flick of a fingertip. Not cheap when you find them but what's a boy to do?