Looking for ideas for a 6 yo that I'm trying to whoa down a bit, and want to just GO and when I take a hold of him he starts slapping his head down to his chest and won't just relax and lope.  I ran him for a year, but took him off barrels because he was running past everything and had no respect for the bit or slowing down.  I might be fighting a losing battle, but I have made progress......he's the most talented and fastest horse I've probably ever ridden, so don't want to give up on him quite yet.  I used to ride him in a pretzel bit with tie down and he was just tight all the time......so I took it all off and put him back in a german martingale and he has lowered his head and walks, trots really nice, but when I ask for a little more, he starts that head slapping, it's like he's trying to hit the end of the tie down but it isn't there.......any help would be great.  I've had his teeth done, chiro etc. so I don't think it's a soreness issue.  He's super sensitive mentally, so when when things go south, I just stop him, let him take a deep breath and start again.  Thank you for listening! 

A lot of times horses will evade and move faster when they're out of balance.

Starting at a walk, I'd go back to basics and work on breaking him apart and getting him to bend at the neck and through the ribs. Teach him now to walk with his nose to his shoulder, starting with gradual tipping of his nose and just seeing his eye to him eventually being able to walk with his nose on his shoulder. Drive him from your feet and encourage his hind end into his face and to bend at the ribs to a circle. Once he gives, you give- feet and hands. Let him straighten out on a loose rein, float out of the circle, and relax. His legs should slow initially, then he'll lose balance and speed up. Just pick him back up, and ask again. Repeat, repeat. Do this in circles and squares. Make sure you're sitting back and not encouraging him with your body. Once he's soft at a walk, move up to a trot. When you release him, he's going to fall apart and speed up at all gaits, just gently pick him back up and start over. I'd do this for several days before I'd even think about asking for this at a lope. 

Don't get mad or stop him when he gets flustered, keep asking the same question- give his body to you, and with every small release, you release and let him straighten. Then let him stop. If its a hard day at a lope, go back to the work at a trot, let him build confidence, and then try the lope again. 

Keep it super super black and white. It takes time to build that muscle and collection, especially at a lope. Give him grace and be patient. (: You've got this!

Send him off to someone with different hands. I ruined one just as talented trying to fix her myself. Sounds just like yours.

I have retrained a few horses like that.  I would much rather slow one down than speed one up but I am a non-aggressive, maybe too quiet of a rider so they fit my style.  I start at a walk , getting them listening again pulling all the junk off their face and progress as needed.  I start off using a loping bridle.  If they start jigging or speeding up at a gait, I redirect them, then move back to the gait, if they speed up again, I redirect again.  Once I get them consistently on a loose rein at a gait I move to the next.  Some respond faster than others and it does take consistent, slow work.  When I get to the lope/canter, once I get them listening through redirection, I start letting them have their face and let them go a bit on a loose rein then ask them to come back to me gradually until some point I can put their hocks in the ground without them rooting out and evading me.  I have one right now that if she sits a little bit, she will revert back but after a refresher over a few days she will lope off on a loose rein and work the barrel pattern quietly when asked. 

He's lacking in fundamentals. Period. And he has learned to evade.

Honestly, these are hard cases to fix. Not impossible, but they are hard. These are bad habits they have learned and it takes a long time for them to be UN-learned.

Based on your description with bits and gimmicks (yes sorry, ties downs and matingales are gimmicks), he just needs to go back to square one. Probably in a basic snaffle and start over completely.

Horses do things to cope with stress and anxiety and sounds like that is what he does when his mind turns off.

Do you have a really, really good colt starter or a really, really good trainer you can go take lessons? While the horse needs training, sounds like you do TOO. Which is why I would suggest lessons.

The critical piece is when you release pressure. If you release pressure when he has his nose in his chest, then he learns that is correct. If he softens his face but you DON'T release him, then he does not associate what the correct answer should be. The timing and release is so very important and we can't help you with that over the internet. You need someone on the ground and in-person watching you to give you that instant feedback on what to do.

Horsess will hit the end of a GM and do exactly what you describe. The pressure the GM puts on the bit when they hit the end scares, hurts, panics them. A GM will also FOR SURE cause one to over break and go to their chest to get away from the pressure.

A bad hard habit to break. Its a little advanced with knowing exactly where your hands are, when and what direction you are applying pressure. Mullen mouth bit and high forward hands are a start to breaking this habit. And consistency! One time of having them overbreak and the correction might need to start completely over.

I haven't read all the replys.

It sounds like something is wrong/hurting him.  Here are things I'd look at before going to a bigger bit. 

Have you had a Chiro or vet go over him?  Have you checked your saddle fit?  Could EPM or an EPM flair up be influencing this behavior?  Are you shoeing him often enough and making sure you don't have any extra toe to help breakover?  Good luck!! 

I'm dislike when people say tie downs are gimmicks...lets be frank, aren't all bits and saddles and stirrups then gimmicks???? "Looking for a sAddle that sits me deep and keeps my feet forward..." "He doesn't run well in this bit, use such and such a bit, it'll help..."  

I'm off subject, it might be a learned avoidance behavior. He might be uncomfortable with working at speed and he has learned how to evade  or try to evade the bit when asked.  Pain between thier ears is much harder to overcome than body pain unfortunately.  Find you a trainer that specializes in it.