When the bits are too big, they floats and the pressure points won't be at the right places. Like too big shoes, the arch won't be at the right place, your toes will float and no matter how much you tighten them, you'll have problem walking with them and finding your balance.
Same if the bits are too small.
Depending on the type of weymouth you have, it would be less noticeable if it is a bit too big, but a too big bradoon would not be really good. The horse will be less willing to stay on the contact. The action of the bit won't be as precise as it's design for.
If it is for a few rides, it won't be traumatic for your horse but on the long run,
your horse would feel better in a 5 1/2 bradoon and a 5 1/2 or 5 1/4 for the weymouth.
Iagree. With remarks from judges about stiffness in the poll and jaw I think this was not a good fit and it may have been a case of that was what the trainer had available. It was for a quite some time and I cant answer as to why the horse was continually trained and shown in the double when the snaffle worked better. I think that may be the million dollar question i need to ask.