Alan
They have a different action on the mouth. A O-ring is a loose snaffle, and the horse will have more play with it. a D-ring is not a loose ring snaffle (the bit is actually conected to the ring), it is in my opinion that the horse will not have the same reaction. Practically all horses from the race track were raced in some sort of D-ring snaffle, I don't like to use that type of snaffle, I like the 0-ring the best, if I were to use snaffle bit, the bigger the bit (thickness) is the less severe and that's the type I'd use when just "hacking" out or "schooling" my horse. It also has a lot to do with the pressure on the bars of the roof of the mouth, or at least my trainer used to say............................
jmo
Linda
