[Ernesto]

I think this is definitely a Felix Mas cover.
Miller comics produced dozens of cowboy comics, usually re-printing stuff from the states. Atlas too had their share of western reprint comics. However Atlas’ Lone Star contained all-British material. Atlas took over in 1956 and the comic lasted until issue number 99 in 1963. Lone Star magazine had originally begun in 1953 as a tie-in promotional tool for Die Cast Machine Tools Ltd range of toys. Toy handguns with holsters and toy rifles were massively popular with children of the 1950s brought up on a diet of Cowboy TV shows. Usually they were “capguns” that made a “loud” bang when paper gunpowder capsules were inserted. These days toy weapons of any type are frowned on, although I see that there are still replicas around.

Link to the book: Lone Star v4 12