My father had four guns the whole time I was growing up.  He always told stories about this or that gun that he had when he was younger, and what he traded for, or sold it for.  He always said "I sure wish I'd held on to that one!" so I learned never to sell a gun.  I don't have a large collection, but I haven't sold any gun that I've acquired over the last 40+ years, so I've got a few.  One of the last one's that I bought used, a Marlin 336 in .35 Remington, appears to need a different barrel, so I'm trying to figure out if I can change it myself.  There is used barrels available on Gunbroker, but I'm trying to figure out how to make sure the headspace is set correctly.  I'd hate to pay a gunsmith to do something that I can do myself!