A tape gun is provided having a pistol-grip type handle supporting a tape dispensing roller upon which a roll of tape is mounted for rotatable dispensing. A tape pressure plate guides the dispensed tape onto a package, with a guide roller mounted in the tape path between the dispensing roller and the pressure plate. The roller is made of or incorporates a magnetic material, such as a neodymium magnet or equivalent. The packaging tape itself incorporates a magnetically attractive material, such as iron dust or wires or other magnetic metal within or on the tape backing in a manner that comes in contact with the magnetic guide roller.