go with the legit legal route and wait it out! if at anytime he treatens or inflicts damage to you or your property and you feel you or anyone else is in danger of severe injurie or death, then use as much force as you feel neccessary! get the restraining order report everything that he says or does that is threatoning! as far as the gun, that could really get you in trouble since your not old enough for a hand gun. just remember you are responsible for every bullet that comes out of that thing! Oh yeah if you are going to carry it atleast get trained up on shooting it!!
but then you have druggy dad comin for you so you will have to a) buy lots of ammo or b) a much bigger gun