A circular stapling instrument, comprising: (a) an anvil defining an annular array of staple forming pockets; (b) a closure system comprising a trocar configured to selectively couple with the anvil and actuate the anvil between a distal position and a proximal position; (c) a firing system comprising: (i) a staple driver, and (ii) an annular array of staples, wherein the staple driver is operable to actuate between an unfired position and a fired position to drive the annular array of staples against the annular array of staple forming pockets when the anvil is in the proximal position, and (d) a casing assembly slidably housing at least a portion of the closure system and the firing system, wherein the casing assembly comprises: (i) a first section comprising: first handle portion, a first shaft portion extending distally from the handle portion, and a plurality of laterally extending male mating features, wherein the first handle portion, the first shaft portion, and the plurality of laterally extending male mating features together define a homogenous continuum of material, and (ii) a second section configured to couple with first section, wherein the second section comprises: a second handle portion, a second shaft portion extending distally from the second handle portion, and a plurality of female mating features configured to receive the plurality of laterally extending male mating features to couple the first section with the second section, wherein the second handle portion, the second shaft portion, and the plurality of female mating features together define a homogenous continuum of material, characterised in that the first section further includes a tubular casing that slidably houses the staple driver. (a) an anvil defining an annular array of staple forming pockets; (b) a closure system comprising a trocar configured to selectively couple with the anvil and actuate the anvil between a distal position and a proximal position; (c) a firing system comprising: (i) a staple driver, and (ii) an annular array of staples, wherein the staple driver is operable to actuate between an unfired position and a fired position to drive the annular array of staples against the annular array of staple forming pockets when the anvil is in the proximal position, and (i) a staple driver, and (ii) an annular array of staples, wherein the staple driver is operable to actuate between an unfired position and a fired position to drive the annular array of staples against the annular array of staple forming pockets when the anvil is in the proximal position, and (d) a casing assembly slidably housing at least a portion of the closure system and the firing system, wherein the casing assembly comprises: (i) a first section comprising: first handle portion, a first shaft portion extending distally from the handle portion, and a plurality of laterally extending male mating features, wherein the first handle portion, the first shaft portion, and the plurality of laterally extending male mating features together define a homogenous continuum of material, and (ii) a second section configured to couple with first section, wherein the second section comprises: a second handle portion, a second shaft portion extending distally from the second handle portion, and a plurality of female mating features configured to receive the plurality of laterally extending male mating features to couple the first section with the second section, wherein the second handle portion, the second shaft portion, and the plurality of female mating features together define a homogenous continuum of material, (i) a first section comprising: first handle portion, a first shaft portion extending distally from the handle portion, and a plurality of laterally extending male mating features, wherein the first handle portion, the first shaft portion, and the plurality of laterally extending male mating features together define a homogenous continuum of material, and first handle portion, a first shaft portion extending distally from the handle portion, and a plurality of laterally extending male mating features, wherein the first handle portion, the first shaft portion, and the plurality of laterally extending male mating features together define a homogenous continuum of material, and (ii) a second section configured to couple with first section, wherein the second section comprises: a second handle portion, a second shaft portion extending distally from the second handle portion, and a plurality of female mating features configured to receive the plurality of laterally extending male mating features to couple the first section with the second section, wherein the second handle portion, the second shaft portion, and the plurality of female mating features together define a homogenous continuum of material, a second handle portion, a second shaft portion extending distally from the second handle portion, and a plurality of female mating features configured to receive the plurality of laterally extending male mating features to couple the first section with the second section, wherein the second handle portion, the second shaft portion, and the plurality of female mating features together define a homogenous continuum of material,