Impossible to answer without the serial number and model
Rifle or pistol?
Depends on if it is a rifle or pistol
I don't know , I would like to find the value of the 4440 1891 ser 171906
100-10000 USD.
1890
10-1000 USD or more depending on specifics
@ 1884
Impossible to answer without a DETAILED description of ALL markings, barrel length, sights, finish, overall condition, box, papers, accessories.
What is the age of a Colt rifle serial SLD25319
You will have to call Colt.
Call Colt and they will tell you.
Can"t tell without seeing it, but if you contact Colt, and get a factory letter, you will have a much better idea. Write down all markings on barrel and frame, including under the grips. Pictures are helpful.