That's a dads job. And since your dad was once a boy (Yes, back in ancient times) there is just a chance he reads any boy you bring home better than you think.
remove the bullets from dad's gun(s) before introducing them.
Try not to worry about it. If you get a boyfriend explain your concerns to him, and tell your dad likewise.
hide the shotgun
your dad won't always have the power he has now.! there will be a time when his demands and rules becomes an opinion.
Don't you think it's kind of silly to worry over something that hasn't happened? Don't you have enough current things to worry about?