I personally don't see any problem with a little bit of lunging like 10 minutes at a time. He nipping does need to be corrected, you can work on this a little at a time too. Desentize him to things around his head, as well as his whole body, then if he bites/trys to bite you, smack him... after you smack him go back to desentizing him.he'll get the idea after a bit.IMO smacking is equal to biting back, and if done PROPERlY will not cause him to be head shy. One thing to remeber is that he is still very young,so don't expect him to behave all the time. I would suggest putting him out with some other older horses wether mares or geldings. They will help to teach him some manners.
On the gun thing. I would not do this, I've had to many horses who are gun shy, the smallest pop of any kind of gun and they literally jump out of their skin. While it might accomplish what you want, the side effects will be terrible. My mare was sentive anyway and would jump and the smallest pop or crack, and just stand there shaking. As much as I tried I couldn't get her over her fear, although I did teach her to come to me/look for me as comfort and not bolt when she heard a noise,but she was by no means over the gun shyness.: a water gun might be ok,but i'd still find a different way if it was me.
Last edited by jwells84; 05-05-2011 at 10:02 AM.