I really see no problem here. You mastered your wife's fear of guns with relative ease. Why not suggest to your father-in-law that he should shoot with you some time? I've found that firm anti-gun folks change a bit when they're actually shooting a firearm. It can be (perish the thought)
fun...
I converted my mother-in-law to a pro-gun person and it's a dang good thing too... My family has always been pro-gun. The only thing I worry about as a pro-gun dad at 29 is that my 16 month old son (at a later age) will go tell the soccer-mom blabber mouths at his daycare that I have a dreaded gun that I routinely carry into public places which allow such carry.
I'm with Delta as well... Leave this laying around...
http://www.gunfacts.info/