A short-lived Western series starring the stunning Tony Young, Gunslinger apparently just didn't show enough to the network to get it even a second season.
The plots are typical western fare: rescuing ranchers' daughters, saving towns from gangs, rounding up bad guys. The main character, Cord, is an early version of the Eastwood antihero. Though he's probably not the first one to dabble in this kind of cowboy character, he should get some credit for being on the frontier, at the time.
The pilot episode is the only one to break new ground in Western series. Cord is sent to bring in a war criminal from the American Civil War: a Confederate army doctor who performed medical experiments on the Union POWs at the infamous Andersonville prison camp. This is uncharacteristically dark for westerns - or really, any TV series - of the time period, and was a promising start, but subsequent episodes drift off into the usual horse opera.
I doubt it will ever see the light of day, again. Just a little blip on the TV screen.