A magazine supporting multiple bone grafts in chambers is coupled to a housing including a barrel. A plunger selectively passes through one of the chambers and along the barrel. A trigger mechanism advances the plunger along the barrel. A selector knob is movable into a plurality of positions, wherein each position employs one of a plurality of stops. One stop prevents the end of plunger from advancing past a predetermined ready position short of the end of the barrel when selected. Another stop prevents the plunger from advancing past a predetermined dispensing position substantially aligned with the end of the barrel when selected. Another stop prevents the plunger from advancing past a predetermined manipulating position beyond the end of the barrel when selected. In the manipulating position, the distal end of the plunger can be used to reposition the bone graft within the spinal disc cavity. Related methods are also provided.