I'm wondering if anyone knows the front sight height of a 686-3 with a 6" barrel? I've heard .278 and .241.

I change mine out for a .250 fiber optic. It partly depends on what load you shoot, but the .250 works for most.

I have a 686-3
If you front sight is like this then the values below will be close:


Sight base to top of sight:


From barrel to top of sight:


Karl

Thanks it's the black pinned blade on mine that was factory buy I have the .250 fiber optic