RE: Pre 64 Model 70 Winchester .458 Win Mag
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.