BP Home
http://www.bufordpussermuseum.com/index.html
Check out the History area and you'll see mention of his guns.
The article about the day he was shot and his wife was killed mentions this:
Buford decided that it was time to change his artillery from a 12 gauge shotgun to an M-16 carbine. He also changed his .41 caliber magnum to a .357 magnum and started driving a new Oldsmobile Toronado. From that day on, Buford vowed to find the men that took a piece of his life away.