Methods and systems are provided for a bore. In one example, a system includes a bore portion for receiving a reciprocating piston, the bore portion having first and second ends between which the piston travels in an axial direction. The bore portion comprises a plurality of recesses, axially spaced apart, and formed in a piston facing surface of the bore portion at a plurality of axial positions, with at least one recess being provided at each axial position. Widths of the plurality of recesses decrease in the axial direction away from a mid-stroke position toward the first and second ends, and depths of the plurality of recesses increase in the axial direction away from the mid-stroke position toward the first and second ends.