For a copy of the owner's manual go to http://stevespages.com/pdf/remington_550.pdf
Tough question, the Remington model 550 is a .22 rifle not a 12 gauge shotgun.
The Remington 550 was made from 1940 to 1946, the 550-1 was made from 1946 to 1970, the 550 had 2 ejecting mechanisms, the 550-1 had 1 floating mechanism allowing it to shoot, shorts, longs, and long rifle shells.
Remington Model 550-1 does not have serial numbers.
serial number on 550-1 remington 22 rifle
Remington.com
You need to go to a gunsmith
was manufactured? All 550's are date code stamped on the barrel. Check related links for information on the Remington Society of America.
Go to Remington's web site and request a manual.
The Remington was first made im 1946
41-70
1945
The Remington Model 550, in various forms, was made from 1946 until 1970. A very few were made in 1941 before WWII broke out.