I am assuming that you have a 1911,not a 1911A1 an it was made for the military not a commercial model (with a C after or before the serial number).That being said I date your colt model 1911 as being produced for the military in 1919.
Colt 1911 .45 serial # 171885 was manufactured in 1917.
your 1911 serial number indicates your 1911 was made by Colt in 1914
Your colt 1911 was made in 1924.
The government issued Colt with that serial number was manufactured by Colt in 1942.
Your Colt model of 1911 dates to the year 1918,with the serial number that you have supplied.
The Colt government 1911 .45 with that serial number was made in 1944 by Remington Rand
1918
By it's serial number.
don't find any 1911 45's serial number ending with a letter. ???
Manufactured in 1978.
1917
1918