"Maurice the FrankenRuger" started out as a brand new Ruger New Vaquero in 357Mag in 2005. It is now...very, very different . 9mmPara conversion, gas-powered shell ejector, magazine feeding, post-modern sights.
I bought an Auto Ordnance "frame kit" in 1990, on which to mount a Colt .22-.45 conversion. I'd owned a couple of .22 rifles for many years, but that was my first purchase.
The longest? That would be a .22 H&R Young American Double Action revolver with a 2 inch barrel that was given to me by a friend in 1969.
Gosh, that makes me sound old!