Bit advice, rubber coated seems to be making mouth sore

[Quartz]

Up until recently I have been using a jointed d ring with copper ss rollers, however my horse would play with it all the time to the point where it would just drive me nuts with crazy horse trying to eat his bit (or felt like this anyway hehehe). Changed to a rubber covered jointed d ring. Although he has been going really well in this bit and seemed really happy, yesterday he was playing up so I checked his mouth and yes the bit has been rubbing on the inside where the lips join.

Its mainly on one side, and already is clearing up with some cream. I am wondering if its some reaction to the rubber.

What bits would you recommend? I am thinking of trying of leather, any views on these? Thanks

 

[touchstone]

Rubber or nylon bits do tend to rub if the horse has a dry mouth. Is there a particular reason you want to try leather? The rollers and copper would make a a horse more active in the mouth, so maybe a simple stainless steel might be better?

 

[Quartz]

I thought about trying the leather, simply because he was happy with the rubber but played too much with the copper and stainless steel.

Could try a simple one, do have one lying around somewhere. Thanks