They make them with an extra tall front sight so that they can be properly regulated with the desired load.
It does answer your question. The sights are not "designed for a cowboy load (ie, 250g at 750 fps) or a more standard load". They are not "designed" for any load. They are made extra tall so that they may be regulated. It wouldn't matter anyway because different shooters will often shoot the same load to a different point of impact.
Are you always this argumentative???
You're right, I only have two dozen single action revolvers. I only have nearly every book ever written on the subject. What could I possibly know???No, but I dont think you are entirely correct either.
One problem with "just using less powder" is that very often, too much airspace in the case results in buckshot patterns instead of groups and there's really no way to tell if the gun is shootin' where it looks because it might shoot 3 inches high for one shot...and 3 inches low on the next...and the dispersal could also sideways.
Because you don't tailor your loads to your sights. You tailor your sights to your chosen load. You find the load that provides the velocity and accuracy with the bullet you want to use and adjust accordingly. I AM answering your question, it's just not what you want to hear. If you're gonna argue with every answer, why ask the question in the first place???
If you just want to find a load that shoots close to point of aim, like I said, they don't "design" (which is what YOU asked!!!) it to shoot a certain load to POA. Why? Because there are too many variables and like I said before, WE ALL SHOOT DIFFERENT LOADS DIFFERENTLY! So you'll have to find out for yourself.
For a given velocity, heavier bullets will print higher.
For a given bullet weight, lower velocities will print higher.
Do you want me to shoot it for you too???
You want what no one can give you