ok
Ive just been reading about where all the different bits fit in the mouth etc to provide different pressure points. The chainmouth sits in the gap between the teeth....but if youve had a thick bit in previously, and the horse has a small gap between his teeth, then the bit wouldnt have been providing pressure on the fleshy bit between the teeth - which is how he might be biting the bit and running (typical if he puts his head down as you described).....but what it does mean, is that the chain may sit in the gap, and you might get an "over-reaction" the first few times you use it because the horse wont be used to feeling any pressure there. It is still much softer than a thin bar bit, or a wire bit, but nevertheless, your horse wont be used to the sensation, so you need to be aware of that! It is supposed to be softer than the straightbar gag bit because the pressure is not always there (if the chain mouth bit is placed low in the mouth), but when it is needed, it is very effective. Otherwise, the bit just falls away in the mouth, and no pressure is there. The "o" ringed chain mouth will be more effective at stopping, but it uses a different motion to the gag, which means that the chain mouth is generally considered softer.
You can increase or decrease the severity of the bit depending on how high or low it is worn. Unlike other bits, I think the chainmouth should be bought slightly wider/bigger than the normal bit used (e.g a 6" chain mouth bit is needed, rather than a 5" straight gag). It doesnt wrinkle the sides of my horses mouth if you want it to be less severe....
ETA - The thicker the chain, the easier it is on the horse because the pressure is spread out more. The thinner the chain, the more severe the pressure is on the horse. The Waterford bit is slightly thinner than the chain mouth....and it also doesnt have as much give in it because the links and the "balls" dont "move" like they do in the chain mouth. Ive been told that the chainmouth is meant to be softer than a gag, but more severe than a straightbar snaffle. Again, severity can be adjusted if the chain mouth is ridden higher in the mouth, and with heavy hands.
Id look for one that was quite thick to begin with (but make sure its not too thick to fit in the fleshy gap between the horses teeth as he will find it easier to bite and run off again). Its worth using bit guards to stop pinching on the sides of the mouth too....
p.s. just seen some made out of bicycle chains....I dont like them - they really are far too severe, and are not allowed in most disciplines!
pps
here is an extract I found about the Waterford bit....thought it might be worth you having a read, but bare in mind that the chain mouth is supposed
slightly less severe than the waterford...
"Why use a Waterford bit?
10 April, 2007
What is a Waterford?
The Waterford snaffle looks like a line of ball-and-chain link. It usually comes with plain loose snaffle rings although you can also buy Waterfords with full cheeks or gag-type rings.
It is a flexible bit that moulds round the horse's mouth, creating an even pressure. It is moveable in all directions and horses find it difficult to lean or take hold of it, giving the rider good levels of control.
Martyn Welsh, bitting expert at Equiport, adds: "Strong horses seem to accept the Waterford rather than a Pelham or curb-type bit as its action is broken when the horse goes to set its jaw. The bit is very loose in the horse's mouth so they seem to mouth more with this bit."
Who uses it?
Fiona Jonason, who is based with leading eventer Polly Stockton in Cheshire, is currently using a Waterford on her advanced ride Zinzan Tiger. Fiona initially rode Zinzan Tiger in a Waterford when he was a seven-year-old, before switching to a snaffle with a lozenge last year, but has now returned to using a Waterford.
"I did ride Zinzan Tiger in the Waterford last year, but only for schooling at home, as he can get quite strong," explains Fiona. "Through the winter, I've been riding him in a Waterford and because he's been jumping so well in it, I decided to leave it in for competition.
"The Waterford suits him because he's prone to cocking his jaw, but this bit stops him latching on to it."
Anyone else?
Other riders who have been spotted using a Waterford include show jumpers Liz Edgar and Nick Skelton. "
http://www.horseandhound.co.uk/horse-care-index/1370/115590.html?cid=1370&aid=115590
