Key Details Mint & Type: San Francisco “S” mint, Proof strike of the 40% silver half‑dollar series Mintage: 2,632,810 Composition: 40% silver, 60% copper clad layers; weight: 11.50 g; diameter: 30.61 mm; edge: 150‑reed design Designers: Obverse by Gilroy Roberts; reverse by Frank Gasparro Historical Notes The 1970 proof sets were among the last 40% silver Kennedy half dollars, as the Mint transitioned to copper-nickel clad in 1971 Only San Francisco struck these for proof sets—there were no proof coin issues for 1970 from Philadelphia or Denver mints
