The prefix letter shows the year of manufacture. 1956 is letter S
That should be 1975
what letter or letters are in front of serial number
Serail number and features
"AD" prefix indicates 1967
About 1973
M prefix to serial # = 1952 manufacture. Jim
"AX" prefix indicates 1981
Harrington & Richardson used the Prefix AT in 1983.
1973
How old is my Topper 88 HARRINGTON AND RICHARDSON GUN serial number
serial number suggests a single barrel, hinged frame Model 1908/08 shotgun - if so - 1920-25.
"P" prefix indicates 1953