Ok so my boy is a very hot 15 yr old arabian gelding. I took him back to a snaffle and generally ride him in that but I compete and ride a lot in his jr. Cow horse short shank with a roller. Now when I first put him in that bit he was great responsive and worked amazingly but now he fights me in it and it takes quite a bit to stop him which resulted in me falling off after he ran me into a fence when I tried to one rein stop him. So today I decided to try my friends wonder gag bit on him and he was an absolute dream low head gave to the bit even got a gorgeous flying lead change from him. I don't want to have to keep switching him I would love to have just one but I'm at a loss as to why he started acting that way nothing was changed on his bridle and I ride him the same everytime.
So my question to you guys is
Do you think a horse can become so used to a bit that he gets bored/learns how to evade it?
I ask this because my friends arab/quarter mare was one that had to constantly have a bit change as she would only work well in one for about 3-6 months before she started acting 'silly'.
These are the current bits he uses
This is the cow horse( this one has a chain)
The wonder gag(this has a nylon chin strap no chain)
horse.com SS Sweet Iron Mouth Wonder Gag Bit 5 in Mouth#
Snaffle(not copper mouthed with leather bit hobble)
Reinsman Offset Copper D Ring Snaffle
However someone suggested this to me (dont have one to try on him)
Barrel Racer Tack Store: Reinsman Ring bit combination w/ twistd wire