100 yards for sure, offhand with either a 6" GP-100 or a 6 1/2" Blackhawk.
I have a 12x12" steel target that I'll set out at 100 yards and hit it 6 out of 6 with a group around 6 to 8", maybe less on a very calm day. That's very repeatable - I once shot all 50 rounds from a box of handloads at it and missed the target once.
Not sure I could hit just any old target that far as the square steel has an advantage to it. You can line up the front blade with the very top of the square and centered horizontally and that gives a nice repeatable sight picture.
Taking it out to 200 yards things get a bit dicier as you have to either raise the front sight in relation to the rear blade or find an aiming point above the target. If you can find a good aiming point - rock, clump of grass or something - just the right distance above the target you can lay 4 or 5 out of 6 into it pretty consistently, but to do that I have to go to a braced kneeling position.
With a tall target like a welding oxygen tank where you can aim near the top and bullet drop still allows a hit 3-5 out of 6 is certainly doable offhand - that's a repeatable percentage. Once in a great while you can get 6 out of 6 but not all the time unless you shoot off of bags which takes all the fun out of it. Wind becomes your enemy at that range, not trajectory. They used to have such tanks out at our range, actual distance was about 220 yards, and now and then I'd show off by making them ring pretty regularly.
That's kind of fun. One calm day I was hitting those 220 yard tanks very consistently, like 4 out of 6, with a little 4" J-frame Smith Model 34 .22. Sight alignment is the crucial factor with trigger control next, after that it's just repeating the same sight picture.
