I made a grave error trying to remove a bead from an 870 express...It was my first gun modification and I mistakenly thought the bead was threaded....it was pressed in...I had to grind the bead off with a dremel and hide the unsightly mess with a truglo bead felt like a moron but its my duck gun and I still love her...
I use a tool called a pin vise to remove beads. Looks like a pen with a collet on the end. Open it up, slip over the bead, tighten collet and unscrew the sight bead.