A surgical stapling device for sequentially applying a plurality of fasteners to body tissue and simultaneously incising tissue is provided. The surgical stapling device is adapted to receive disposable loading units having staples in linear rows whose length can be between about 30 mm and 60 mm. The disposable loading unit includes a proximal body portion, a mounting assembly and a tool assembly. The mounting assembly is secured to the proximal end of the tool assembly and pivotally mounted about a pivot axis to the distal end of the proximal body portion. A support member or blow-out plate assembly is positioned on opposite sides of the pivot axis and extends between the proximal body portion and the mounting assembly. An axial drive assembly is slidably positioned between the support members and is translatable through the cartridge assembly to eject staples from the cartridge assembly. The support members prevent outward buckling of the axial drive assembly during actuation of the device especially when the tool assembly is articulated. Preferably, a protrusion is provided in the proximal body portion of the disposable loading unit at a position to frictionally engage an articulation link. Engagement between the protrusion and the articulation link retains the articulation link at a fixed position within the proximal body portion to maintain the tool assembly in a desired orientation until a predetermined axial force is applied to the articulation link. The disposable loading unit also preferably includes a locking member which is operably connected to the axial drive assembly. The locking member provides an audible and/or tactile indication that the device has been actuated.