I might devote a topic to this later, but this is a wonderful tradition. Don't you wish your Grandad had bought a Thompson back when they sold them at hardware stores? I sure wish mine had and the bitch of it is, when ever he went to the store to get thing for his dad, he would just marvel at them.
Anyhow he did start a real decent collection anyway, which every generation has added to. You, and others, may not recognize the position you are in. We will be the LAST generation able to purchase Preban military rifles and postban 922r variants. These will NOT be readily available in 20 years. My advice is to pace yourself. Don't grab 10/22 and shit just to fill the safe, take your time and buy meaningful firearms. I can buy an '03 anywhere but I can't buy the one my Grandfather had, he had to save it for me. Family guns are more than investments or inheritance. They are heritage and family identity. Much like Japanese families who pass family swords.
Fortunatly the split was fairly easy. I'm a military guns guy and my brother is mostly a hunter. He did grab a few exotics like the gas trap M1, The baby Luger and the Liberator(the only one that really hurt, I still don't have one), but the bulk of his collection is EVERY German Wheatherby, so many Brownings even I don't know all of them and the Remingtons, Winchesters, etc. He knew I was the military collector so he was cool about letting the Mausers, Lugers, P-38s and such go my way. Most of the modern military H&K,AUGs,AKs,ARs & FALs where added by me.