There isn't, "champing" is the correct and only way it's meant to be said since it refers to horses that literally champ at the bit in their mouths when feeling restless.
Chomping is simply a similar action involving the jaw but doesn't infer impatience.
Champing.
Both are correct. Chomping leans towards American usage.
I'm on the west side of the Atlantic. I wasn't aware there were two ways of saying it.
There isn't, "champing" is the correct and only way it's meant to be said since it refers to horses that literally champ at the bit in their mouths when feeling restless.
Chomping is simply a similar action involving the jaw but doesn't infer impatience.