High calibur rifle (3.5e Equipment)
From D&D Wiki
The High Calibur Rifle holds 5 Bullets. As long as it holds bullets, you can reload it by pulling the reloading lever (a free action). Loading a new case of 5 bullets is a full-round action that provokes attacks of opportunity.
The High Calibur Rifle can't be used while standing up unless you have 20 strength or more. It takes a move action to set up or pick up to move and must be fired prone normally.
Any enemy within 250ft of the shooter knows the general direction of the shooter when the gun is fired if they pass a DC 10 listen check.