By the end of the 1930s the only major U.S. firm manufacturing CF ammunition which did not use patented expanding bullets of a compound type was the Western Cartridge Company. But finally in 1940 the Winchester-Western Silvertip was released.
The design was quite simple. The jacket was made of conventional GM, the core of a lead alloy. The core, however, was encased in a thin jacket of nickel-silver, closed at the nose, which gave the bullet its unique appearance and name. Originally, the liner extended the full length of the bullet jacket. Later, the liner was changed to a softer, thin aluminum alloy that covered only the front half of the core. Additionally, the bullet jacket mouth and silvertip was given an octagonal interior shape which enhanced bullet expansion.