Around 1960, comic book superheroes were making a comeback...
...and both Zorro and The Lone Ranger were two of the hottest shows on TV!
So, it was only logical that comics publishers would, once more, combine genres and unleash a number of new (and revived) Masked Western Heroes™!
The idea that a supposedly-non-violent guy would have a basement full of customized weaponry would trigger alarms today, but back in the early '60s, it seemed perfectly natural...if a tad hypocritical.
And why can't Clay tell Nan and her grandfather that he's GunMaster...beyond the fact that it would make his stance about non-violence look foolish?
His premiere story in Charlton's Six-Gun Heroes #57 (1960) was scripted by Joe Gill illustrated by Dick Giordano, Frank McLaughlin, and Sal Trapani.
This was Charlton's second contribution to the sub-genre.
The first one was a more traditional type known as the Masked Raider, whose gimmick was that he had an eagle as his sidekick!