Abstract: A novel continuous web of composite packaging film for making packages having improved openable and reclosable interlocking seals, the seal having male and female portions of arrowhead shape in cross section, snap detents, and being formed transversely to the direction of film flow during package formation at line speed. The packaging film is provided at package length intervals with thermoformable strips secured thereto transversely to the running length of the film, and is fed to a modified standard vertical form, fill and seal packaging machine where the film is formed into a bag with the thermoformable strip inside in ends abutting folded facing relationship at the upper end of the bag, product deposited into the bag, the bag sealed, the reclosable interlocking seal formed, and the bag severed from the next bag being formed.