A cartridge assembly for a surgical stapler has a first cartridge portion, a second cartridge portion, and a housing. The housing is shaped and configured to provide a fulcrum about which an anvil may pivot. Each of the first and second cartridge portions has an upper surface for engaging tissue, and a slot configured to house a staple. A proximal portion of each of the first and second cartridge portions has a guide portion having at least one of a channel or a protrusion for guiding at least a portion of an i-beam. The second cartridge portion is removably coupled to the first cartridge portion to form a channel between the first and second cartridge portion. Each of the first and second cartridge portions has a recess proximal of the fulcrum, the recess shaped and configured to receive a proximal portion of the anvil.