Join Date: Sep 2009
Location: Tampa Bay area, FL
Alright, first of all, changing to a harsher bit is never a way to solve the problem, even more so because you probably don't have experience handling a bit like that in a horses mouth.
Have you checked that his teeth have been floated recently? If he did come from a less-than-ideal home, that may be a problem.
Also, has he been worked recently? I know before I got my horse Ice, he was well cared for but never ridden, so when I went to go put a bit in his mouth, he did everything that your horse is doing just because it was so uncomfortable. After a few weeks, he started accepting the bit (once it was in his mouth) but then a few more weeks and he started to throw his head every time I tried to put the bridle on--I now use a hackamore and he's much happier with that.
You might also want to check how the bit fits....you don't want to corners of the O/D-rings slipping in to his mouth, nor hanging loose off the sides...when he's standing still with his mouth closed, you want there to be two "smile lines" or wrinkles in the edges of his lips where the bit comes in contact.