Five Against Death — J.R. Roberts

The town of Los Alamos is about to be swallowed whole by the notorious bandit El Gigante. Only four dare to fight back -- but they know it will be a losing battle unless Clint Adams agrees to step in. The Gunsmith isn't about to sell his hide for a paltry one hundred dollar reward and rumors of a hidden treasure, though...until he meets the sheriff of Los Alamos, the seductive Carlotta Cortez.

It seems El Gigante is more hell-bent on the sultry sheriff than on the fabled treasure of Los Alamos. Perhaps the Gunsmith is, too. And that makes for a rivalry as bitter -- and deadly -- as poison....