I think its perfectly fine to put conditions on the gift, especially if you are intending to start an heirloom tradition. The gift is more than just the gun. Lots more, but not really a tangible thing.
Threads like this choke me up, and if I dwell on it, bring tears to my eyes (alone, at home, where no one will see them
), because they make me remember the guns I have received, and the loved ones who left them behind for me to remember them by.
I know that there are some of us who only think of firearms as tools, which, of course, they are, but to me, some of them are intensely personal items.
If you get it, you get it. IF you don't there's no way I can explain it to you, other than that when I use my grandfather's Ithaca, or my Dad's Colt, though they are both long gone, they are with me still.
This is yet another reason why I detest the "turn them all in" gun banners. If they had their way, they would steal from me, precious memories, things beyond any earthly price, and worse, they would steal them from my children, and their children as well.
Family isn't just blood & legally defined relatives, its also those whom we choose, and who chose us in return. Passing along guns, or anything with significant memories and emotional attachment is something we do, and understand.
History, tradition, honor, the things that make us, "us", last as long as there are people to remember them, and us.