i was wondering what difference was between the "f" and "g" models. here is what the Beretta web site says about the px4 storm, The Px4 Storm includes multiple trigger operating modes, which include our standard F model - double/single action; C model - constant action; D model - double action only; and the G model - double/single action with return to fire feature. All full size Px4 Storm Pistols feature a rotating barrel which makes for a low profile design with one of the strongest actions available. Also, you have a choice of three backstraps, three magazine release buttons, and two slide catch lever sizes. does anyone know what the "return to fire feature" is? sorry if this has been discussed before but i couldn't find it. Thanks.