BLOOD TRAIL   When a shootout leaves Pinkerton man Charlie Siringo and his tracker Tom Horn laid up in Las Vegas, they're lucky to be alive--and even luckier to bump into their old friend Clint Adams. Despite their injuries, they take up the trail again, this time with the Gunsmith along for the ride. But the cattle rustler they're chasing down is one nasty character, and if one of the wounded men stumbles, it could land Clint in a grave position. OVER 15 MILLION GUNSMITH BOOKS IN PRINT!