A surgical instrument for stapling tissue, the instrument comprising: (a) a body; (b) a shaft assembly extending from the body, wherein the shaft assembly comprises: (i) a stapling head assembly, and (ii) an actuator; and (c) an anvil configured to be selectively coupled to the actuator, wherein the anvil is configured to cooperate with the stapling head assembly to staple tissue, wherein the anvil comprises: (i) a head, and (ii) a shank extending from the head along an axis, the shank comprising: a proximal end, a distal end, a lumen extending from the proximal end toward the distal end, an engagement feature between the proximal and distal ends, and an outer surface, wherein the engagement feature is in communication with the lumen such that the engagement feature is configured to move relative to the axis in response to the actuator being directed into the lumen, wherein the engagement feature is configured to selectively couple the shank to the actuator, wherein the proximal end of the engagement feature is radially fixed relative to the axis; characterised in that the outer surface comprises a textured surface; and a portion of the textured surface is positioned coincident with the proximal end of the engagement feature. (a) a body; (b) a shaft assembly extending from the body, wherein the shaft assembly comprises: (i) a stapling head assembly, and (ii) an actuator; and (i) a stapling head assembly, and (ii) an actuator; and (c) an anvil configured to be selectively coupled to the actuator, wherein the anvil is configured to cooperate with the stapling head assembly to staple tissue, wherein the anvil comprises: (i) a head, and (ii) a shank extending from the head along an axis, the shank comprising: a proximal end, a distal end, a lumen extending from the proximal end toward the distal end, an engagement feature between the proximal and distal ends, and an outer surface, wherein the engagement feature is in communication with the lumen such that the engagement feature is configured to move relative to the axis in response to the actuator being directed into the lumen, wherein the engagement feature is configured to selectively couple the shank to the actuator, wherein the proximal end of the engagement feature is radially fixed relative to the axis; characterised in that the outer surface comprises a textured surface; and a portion of the textured surface is positioned coincident with the proximal end of the engagement feature. (i) a head, and (ii) a shank extending from the head along an axis, the shank comprising: a proximal end, a distal end, a lumen extending from the proximal end toward the distal end, an engagement feature between the proximal and distal ends, and an outer surface, wherein the engagement feature is in communication with the lumen such that the engagement feature is configured to move relative to the axis in response to the actuator being directed into the lumen, wherein the engagement feature is configured to selectively couple the shank to the actuator, wherein the proximal end of the engagement feature is radially fixed relative to the axis; characterised in that the outer surface comprises a textured surface; and a portion of the textured surface is positioned coincident with the proximal end of the engagement feature. a proximal end, a distal end, a lumen extending from the proximal end toward the distal end, an engagement feature between the proximal and distal ends, and an outer surface, wherein the engagement feature is in communication with the lumen such that the engagement feature is configured to move relative to the axis in response to the actuator being directed into the lumen, wherein the engagement feature is configured to selectively couple the shank to the actuator, wherein the proximal end of the engagement feature is radially fixed relative to the axis; characterised in that the outer surface comprises a textured surface; and a portion of the textured surface is positioned coincident with the proximal end of the engagement feature.