Hello Nitrox

When I fitted the 4x Zeiss and claw mounts to my 9.3x74R double, it would not regulate with the scope. Cannot remember exactly how it changed but it used to shoot into about 2-1/2 to 3” (2x right-lefts) at 100 yards with the open sights, but when the scope was added it did not shoot to an acceptable standard at all, like around 5 inches.

I re-regulated the barrels (heat and move etc) using the scope at 100 yards. Now it shoots around 2” groups (2x right-lefts) scoped at 100 yards and (when my eyes are up to it) just a tad over 1” with the open sights at 50 yards….. More than adequate. I think have some pictures of the groups somewhere, I’ll try to find them and post them.

Found them

With the open express sights @ 50 yards (and yes there are 4 shots there, 3 in one hole)

and with the 4x Zeiss @ 100 yards

I don’t have any targets to back this up, but when I can see well enough, my 9.3 double will comfortably hold four shots into about 2-1/2 to 3” (2x right-lefts) at 100 yards with the open sights. For me I would consider that excellent field accuracy. When I do my part, it has killed everything I've shot it at at those sorts of ranges.

If it were me, and considering the wonderful caliber you have chosen, and considering you are going to scope sight the rifle, then I'd get the rifle regulated at 100 yards with the scope sight, and have the open sights zeroed to 75 yards. You wouldn't have to worry about trajectory over normal open sight ranges and you can zero the scope sight to what ever distance you wish.

And don’t forget, express sights really aren't the best suited to head shooting rabbits at 100 yards anyway

Best
ALEX