A surgical stapling instrument, comprising: a first side; a second side; a longitudinal axis; a first housing portion, comprising: a staple cartridge attachment portion configured to operably support a staple cartridge; and a first lock rail extending from the first housing portion and along said longitudinal axis; a second housing portion, comprising: a jaw member configured to operably support an anvil configured to deform staples deployed from the staple cartridge; and a second lock rail extending from the second housing portion and along said longitudinal axis; a pusher bar configured to move a staple driver relative to said staple cartridge attachment portion and said jaw member; and an actuator configured to receive a force thereto, wherein said actuator is configured to be moved between a first position and a second position, wherein said actuator is configured to be moved along said first side when said actuator is in said first position, wherein said actuator is configured to be moved along said second side when said actuator is in said second position, and wherein said actuator further comprises a channel configured to receive said first lock rail and said second lock rail; wherein said first lock rail and said second lock rail extend from said first side, wherein said channel is configured to receive said first lock rail and said second lock rail when said actuator is in said first position, wherein said first housing portion further comprises a third lock rail extending from said second side and along said longitudinal axis, wherein said second housing portion further comprises a fourth lock rail extending from said second side and along said longitudinal axis, and wherein said channel is configured to receive said third lock rail and said fourth lock rail when said actuator is in said second position. a first side; a second side; a longitudinal axis; a first housing portion, comprising: a staple cartridge attachment portion configured to operably support a staple cartridge; and a first lock rail extending from the first housing portion and along said longitudinal axis; a staple cartridge attachment portion configured to operably support a staple cartridge; and a first lock rail extending from the first housing portion and along said longitudinal axis; a second housing portion, comprising: a jaw member configured to operably support an anvil configured to deform staples deployed from the staple cartridge; and a second lock rail extending from the second housing portion and along said longitudinal axis; a jaw member configured to operably support an anvil configured to deform staples deployed from the staple cartridge; and a second lock rail extending from the second housing portion and along said longitudinal axis; a pusher bar configured to move a staple driver relative to said staple cartridge attachment portion and said jaw member; and an actuator configured to receive a force thereto, wherein said actuator is configured to be moved between a first position and a second position, wherein said actuator is configured to be moved along said first side when said actuator is in said first position, wherein said actuator is configured to be moved along said second side when said actuator is in said second position, and wherein said actuator further comprises a channel configured to receive said first lock rail and said second lock rail; wherein said first lock rail and said second lock rail extend from said first side, wherein said channel is configured to receive said first lock rail and said second lock rail when said actuator is in said first position, wherein said first housing portion further comprises a third lock rail extending from said second side and along said longitudinal axis, wherein said second housing portion further comprises a fourth lock rail extending from said second side and along said longitudinal axis, and wherein said channel is configured to receive said third lock rail and said fourth lock rail when said actuator is in said second position.