Citizens not breaking any laws should not have to get on their knees for anyone (unless by choice). The cops had no reason to stop him for open carry. If he had other run ins with the cops and was treated the same way, then I understand why he intentionally went out and recorded this. It's time to expose the crap that legal gun owners have to put up with from some cops.
If he was within his rights to carry open, that is his right. Laws are not made by police, and they need to understand that. Their opinion is just that.
Open carying in a state where it is legal in one form or another is not probable cause to stop someone, case law supports that. The officer had no right to even stop him, let alone draw down on him when clearly no law was being broken. Since he stopped him, he should of just looked at his permit and then parted ways, not detain him for 40 minutes, force him to the ground and I'm sure a couple of knees were forced into his back.