Ned is correct.  The 1895 Winchester-Lee (straightpull) was in 6mm/.236USN.  The magazine required a 5 round metal clip that dropped out the bottom of the magazine when empty.  The metal clip is rare.  The cartridge is rimless and was ahead of its time (given the propellants that were available when it was in use).  The Winchester-Lee has a lot of fragile parts and kind of 'cranks' into battery rather than being a true straight-pull.  James Paris Lee of Remington-Lee and Lee-Enfield fame was the designer.  In addition to the U.S. Navy and Marine Corps contracts, Winchester made a civilian sporting model.  When I was a young collector (1960's), I use to see a couple of military Winchester-Lees  that were sporterized by Bannerman (at Michigan gunshows).  These had letters of documentation as having been salvaged off the U.S.S. Maine.  When the Krag was adopted by the U.S. Army, it had rivals.  Other branches of the service were allowed to and did select their own arms.  Chuck McArthur