Approximately how old is the Winchester Model 1904 22 rifle?

The Winchester Model 1904 was never serialized. The model was introduced in 1904 and discontinued in 1931. Here are some ways to get a little closer: If you have a crescent buttplate, 1904-c.1910, hard rubber shotgun type buttplates after c.1910. Light checkering on the cocking piece through c.1914, heavy knurling afterward. Barrel markings on top of the barrel through c.1917, on the side afterward. WP proof mark in an oval after c.1918. Diamond-shaped cutout on steel pistol-grip piece, c.1927-1931.