Charging pony!

[AEH]

My 14hh recent loan pony, 25 year old!! charges madly into jumps I have no idea how to stop this? She is ridden on the third loop of a gag with flash and running martingale ( i know this is probably too much but she came ridden in all this tack, so I have left her as is) She used to be a riding school pony so trots around like a llama, if i give her a loose reign she takes off in canter. I school her all the time but its so hard to create bend and suppleness as shes so on edge all the time, you literally need no leg at all. However she wont bolt just will go and go and go.... I really need help as I cant jump her and she is starting to knock my confidence but I really don't want to send her back. Any help will be appreciated. In addition she pulls like crazy in a simple snaffle as have tried. thanks

 

[Meowy Catkin]

How about a bit with a curbchain eg a Kimblewick? I have have found that alot of ponies go better in them than they do in gags (which should be used with two reins - one on the snaffle ring).

What's she like when you hack her? Maybe she needs a break from constant schooling to get her to relax?