I'm not entirelly sure that a gun-rack lock is a good lock for learning... I think that your father should really give calling a locksmith one more thought.
...and besides - i've looked through all your posts, and I'm not totally convinced that it's your father who wants this lock to be opened. If there's even a chance that you are trying to do it behind his back...well... try to look at it from our perspective... Helping an underaged person to get his hands on weapons with live ammo is not really the smartest/safest thing to do.
I'm not saying that this is the case. I'm just saying that we can't really be sure.
As i wrote before - i believe that a professionall locksmith should give it a go. And besides - if I was a father of a son, I would really feel uncomfortable knowing that my young son knows how to open my gun-rack. That lock is there for a good reason...
I hope i'm not being too harsh.
Anyway, good luck.