According to Remington.com, the model 870 shotgun has been the most popular shotgun ever sold by Remington Arms. This shotgun was originally designed with a front-sight-bead riveted to the shotgun rib. The front-sight bead can be removed to add other sight applications.
Unload the shotgun completely. Visually inspect the weapon to ensure no ammo is present.
Position the weapon in a padded gun or barrel vise. Ensure that the sight bead is accessible. Lock the vise down tight.
Place a razor blade flat on the shotgun rib. Center and butt the blade edge up to the sight bead. The blade edge will be pointing away from the receiver.
Grab the sight bead with the cable cutters. Lift up with the cutter handles using firm pressure. The sight bead will pry out of the rib.