bring up the weapon wheel, highlight your pistol and scroll through the different pistols available. the weapon wheel lets you have one of each type of weapon "at the ready" but the other guns are still there and selectable. notice when you highlight your pistols that there are 2 arrows, one in each direction. indicating there are more weapons available to be selected. i used an xbox 360 pc controller, and i selected the different weapons by pressing sideways on the d pad. not sure exactly how it is done with mouse and keyboard. scroll wheel perhpas?