Look's like they were made from 1899-1915, serial number range was 10,000-175,000. If it has an octagon barrel it's from that era. It was re-introduced in 1920 as the 1899B but with a round barrel and made until 1930. Ser# range was from 200,000-344,000.

http://www.savage99.com/savage99_dates.htm