I'm having trouble with my 3 year old. Turning 4 in May.  When we lope circles he wants to fade and keeping fading to the outside. He lopes nice but wants to make his circles bigger and bigger. I use my outside foot to gather him back in but he continues to do it. Making it a fight to lope circles. It has always been a problem. i'm wondering if somones has a suggestion on what to do with him? Bit? I ride him mostly with gag and lifter. I'm trying to make his circles smaller and its a problem. He has a good soft mouth but he is a big horse. He is right at 16 hands tall. He is going to be a barrel horse. i have started him on barrels but this needs to be worked out!

Thanks!!!

I had a similar problem, but it would only come out during a run. My horse would arc way out of his second and brace on me. I kept using the outside leg also and then went to a clinic and the clinician looked at my video. It turns out he was blocking his shoulder and stiffening. He put me into circles with my hand to my hip and kicking with my inside leg so he would start reaching underneath with his inside hind. My kicking with the outside leg was actually making the problem worse. The first few times I did this, it was ugly and we both had to work through it. The first runs back after this clinic, VOILA!!, he turned his second barrel without moving out. I now work on that exercise at a walk everyday. I only have to do it at a trot or lope if he gets to ignoring me and then we have a moment and his brain clicks back into place. 

Are you putting your inside hand to your hip or your outside to your hip? Thank you so much! I'm going to try!

I would wonder if there's a soreness problem. 

for whatever reason, he's not following his nose. I would put a draw bit on him and do an abrubt  one rein stop to the inside of the circle every time he stepped off the circle. You might have to do it every few steps when you start but he'll get the idea to honor the rein pretty soon.

I guess I would say I pull to the outside. Once they get it, then you can quit pulling that far back unless they need a little reminder. When loping through then you can just set you hand where it would normally go and just use your little finger to provide that reminder unless he tries to move out and then you can pull him in. Like someone else said, always make sure there is no soreness, but a lot of the time, we create our problem (hand raised here!!) and just have to correct it and ourselves.

It would be helpful for you to post a video.

You might be doing something different in that direction (that you don't the other way) that is allowing him to drift.

It could be something as simple as which seat bone you are placing your weight. Some horses are sensitive to that.

Without seeing a video of any kind, my guess would be that he lacks shoulder and ribcage control. Work on that at the slower gaits because the hole is likely there too and just manifests when you speed up to a lope.

Quit riding the head and ride the butt. The butt is the propulsion unit. Sit deep and quiet and keep your hands low and quiet. Look to the inside of your horses head toward ground. Don't crank the head around. If you can barely see side of eye you have enough bend to lope circles.

Are you leaning or slightly shifting your weight? This can make one drift. Are you keeping him too bent? This can make one shift. Does he have very good shoulder control with leg and/or rein pressure? This can help keep them from drifting as long as you are subtly asking him to step out.

Thank you for all the advice. I just had him adjusted. He is really rough to ride loping. I've had to work really hard to get my body adjusted. I found the magic bit yesterday!!! I was soo excited. I decided to just try to different bits that i hadn't thought about. It's the wonder bit. It helps with poll control and shoulder control. I think the suggestion of me working on his shoulder control was a good suggestion. That bit was like the magic button for us!