There seems to be a tradition in pulp SF illustration - a tradition extending all the way up to the promo photos for 1977's Star Wars - that the hero holding the gun must be shown as firing it - usually at nothing, and depicted always in the most ignorant, lackluster way.
'Sparky' here just set off a small, controlled explosion in his hand, firing a projectile against a glass object, shattering it. The action depicted here is going to be a lot more violent than a feeble straight-edge line of yellow going to some broken pottery, while the languorously stretching girl looks on with placid expression. - You'd think she'd flinch, at least; a gunshot at close quarters can do permanent hearing damage.)
The “Captain Future” comics ran to the same formula - always, always he is "firing" his proton pistol at the bad guy, without anyone, including the bad guy, even noticing - and neither is he ever shown actually hitting his target, which is unfortunate, for the raygun's "beam" was a close-set series of expanding smoke rings with an effective range of about five feet, and I'd like to know what harm that was intended to do!