JeanKS- Welcome to a great Krag collector's sight. You won't find more information about your beautiful family heirloom than right here. Many collectors will probably chime in with varying types of information to help you research your Krag.

You have a lot of correct information so far. You have a Model 1898 Krag rifle that appears to have been made in 1900 which matches the cartouche. The pictures you posted are real helpful in seeing exactly what you have. An additional picture of the cartouche would also be nice to see.

Your rifle seems to be full length without having had the barrel or stock cut down which was frequently done to make sporting and hunting rifles. The rear sight looks like an original 1898 rifle sight that has seen arsenal alteration done in or around 1902 to smooth the edges of the rear plate and add a "Sergeant Peep" device that could be turned up to sight through. These were added to assist sharp shooters who competed with Krag rifles in the early 1900s.

The "P" stamp behind the trigger guard is simply a proof mark that signifies the rifle had undergone proof firing. The cartouche signifies the date that the completed rifle was accepted to be used by the military.

Your rifle looks to be in really nice condition. It doesn't seem to have any bad pitting on the outside from the pictures, the stock looks very nice with good color and little damage. The condition of the bore would be nice to know which can help a little more to determine approximate value. Others have the complete listing of serial numbers of listed and documented rifles with known history. Yours is unlikely to have such because very few records were kept about documentation. But, that will be done by someone else soon.

I would say that your family heirloom has a resale value to a collector of at least $1200 if there is no documentation of the serial number. The condition of the bore can add or subtract a little from that price. Insurance value would be at least $1500.