I tried a hackamore on my horse last night, partially as a potential jumping 'bit', and partially just for the heck of it. It seemed to work really well for getting a balanced canter, and he was pretty relaxed in it. My problem is that I've never ridden with a hackamore before, and I'm not sure how to. Do I keep contact as if it was a bit, or do I keep loose reins and only add contact for breaks? The canter was nice and he was happy to stretchy trot the whole time, but there wasn't much in the way of 'flat work'. He steers by leg and rein pressure, so steering in't a problem.
I have had two mares who do not care for bits at all so rode in hackamores. The one mare I rode just like I would if I had a bit in her mouth. She liked a lot of contact and would actually stretch down and into the hackamore on the flat. the other I rode a little more light on the reins. Still steady but light contact and a heavier half halt as needed. I use the same hackamore as you posted which is not mechanical. A mechanical hackamore has a moving hinge and can be a bit more severe. (totally depends on the hands on the reins) I have done gaming in one of these on a very strong pony. Really only used it for brakes.
I would just see how your horse goes in the hackamore and go from there. If he seems to want the contact go with it, if not just use more for corrections.
I use a slightly softer hackamore with less leverage for jumping, and use it just like a bit~ same amount of contact as with a bit for dressage. http://www.smithbrothers.com/product...FQ2znQodJkYAdQ
It is this one exactly, but I wrapped the chain and rope nose in lots of vetwrap.
I switched to this hack because the mechanical one had too much leverage for Pie, and I was running into the same problem as you. Slack-check was the only way to use it... it was too strong for him to push into and seek the connection.
This hackamore has completely changed our jumping!
I have been riding my TB mare in the same hackamore for years. The only time she uses a bit is when we do a combined test in the dressage segment. Where my mare didn't like or fussed with contact with a bit, I find I can take contact with the hackamore. We have the same type as you do. We use it so much that we have one for trail riding(the kind you have) and a dress one that is the same color as her good bridle. For the nose band, I buy halter fleeces with velcro to keep the fleece from compressing and rubbing her nose.
Here are a couple of pictures of my girl in her dress and schooling hackamores http://www.flickr.com/photos/simbalism/6937198746/ http://www.flickr.com/photos/simbalism/7293686384/
I kept light contact on the mech hack I used on my bargy strong gelding. Once he knew it was on I only needed light contact. The shanks give you a lot of leverage so you really have to be gentle. The biggest issue I had was that although I had plenty of whoa I didn't always have fine tuned steering. It's why you see jumpers in a hack with a bit under it.
I use the LG bridle on my horse who cannot tolerate tongue pressure. http://www.lg-bridle.com/. It was developed by a german dressage rider. I use the model with no shanks or chain (just a leather strap).
I've used the same hack you pictured with the short shanks and found it was too strong. I only used light contact.
I like the LG b/c you can use it as a side pull or if you need more leverage you can hook your reins so that you have a little.
I use light contact with this bridle too. If I don't he starts to lean and get heavy.
I have the same hackamore in the OP's link. I swapped out the chain curb for a leather one. I can get very subtle cues in with it and often don't really notice that we don't have a bit.
The key is to find the contact that removes the slack from the curb without putting pressure on the jaw. Then the horse can feel a little squeeze of the fingers on one side. There is some initial training involved to get the desired response, but it doesn't take long.