Belmont Books B60–2011, 1970. Cover artist: John Duillo.
Jack Slade was a house name at Belmont and the Lassiter westerns were written by various authors. Lynn Munroe makes an argument for Peter McCurtin as the author of Gunfight at Ringo Junction.
Judging from the swash glyphs – especially R and S – and the g with the upward-pointing ear, this isn’t Bookman Bold Swash, but Photo-Lettering’s Bookman Italic Swash Heavy, see PLINC Bookman Swash.