An apparatus (10) loads partially-formed open-ended cartons (12) onto respective mandrels (14) of a turret (16) that indexes cartons through work stations. A conveyor (18) propels the partially formed cartons (12) along a load path (20) and loads them onto respective mandrels (14). A loader guide guides the partially formed cartons (12) along the load path (20) and maintains them in axial alignment with the respective mandrels (14). A loading pusher (24) carried by the conveyor (18) engages successive partially formed cartons and propels them along the loader guide and onto the mandrels (14). A controller (30) commands a loading servo motor (28) to advance the conveyor (18) and transport each partially formed carton (12) along the load path (20) and into a delivered position on one of the mandrels (14) and then to reverse the conveyor (18) momentarily before the turret (16) indexes. The advancing, withdrawing, and indexing steps are repeated for second and subsequent partially formed cartons (12) and mandrels (14).