An adjustable shoulder rest for a rear stock for a rifle or shotgun, with slidable adjustment features at the butt plate to customize the shoulder to firearm interface, providing diverse adjustment options pursuant to user preference and/or circumstances of use. The present invention further provides a pivotal, slidably-adjustable shoulder rest to facilitate customized position adjustment to the firearms orientation vis-a-vis the operator, including the option to provide a swivel connection for adjustment of the firearm during operation as well as the option of providing haptic feedback to communicate to the user or otherwise facilitate line of sight alignment of the firearm at various angles relative to the longitudinal axis thereof in line with one or more sighting apparatus mounted thereto