Well, it is good that you at least told him of the money he stood to lose. Depending on condition and grade, that gun may well be worth upwards of 10 large. Its a good buy for sure. If he doesn't mind losing out on that kind of cash, well, a gift is a gift.

As a token of good faith, I would try and find out exactly what this guy likes to do or something. You know, if he is into fishing or something, buyhim a nice new reel or something like that. Just a get and give back.

Hold on to that gun when you shoot it.