Colt 1873 SAA
A few honorable mentions would include the Winchester 1873 repeating rifle, M1903 Springfield, SKS, Mosin Nagant, and the Remington 870.
mosin? m1? wow, im surprised you know how to work a computer at your age. naw man, i just based my list off of what i liked to fire, and what i remember people carrying the most. im guessing the old you are, the older the weapons.