if double action revolver it was probably made about 1923
if a New Service model made about 1920
Proofhouse.com has Colt sn tables.
what is the manufacture date of a .38 police positive special serial number b 81
No way to answer without the caliber.
Sorry but we would need the serial number to answer.
1920
1927
1918
No published sn data
1958
1950
The year of manufacture for serial number 25035 is 1947.