Two unidentified Marines pose for a portrait in Manila, circa 1901. From the James B. Manion Collection (COLL/86) in the Marine Corps Archives & Special Collections.
Note the Krag-Jorgensen rifles in .30-40 Springfield and the 45-round Mills-style cartridge belts. While the Navy and Marines of the time predominantly used 6mm Lee rifles (until the 1903 Springfield was adopted) there was also widespread use by the sea services of the Army’s Krags and images of Devils and Bluejackets with Krags in Cuba in 1898, the PI in the 1900s and the relief of Peking in the Boxer rebellion all exist as do Krags with Navy acceptance marks.
According to a post over at the Krag collector’s forum, the Navy was still buying Krags from the Army as late as 1911, using them for training in WWI, and still had ammo on the shelf for them as late as the 1960s.