Pictures would let us tell you a lot more about it. Octagon barreled 1899's were made from 1899 to about 1917, then discontinued. So not rare, but bring a premium over the round barreled ones which are more common.
“
The Savage 99 Pocket Reference”.
All models and variations of 1895’s, 1899’s and 99’s covered.
Also dates, checkering, engraving.. Find at
www.savagelevers.com