For sighting in at 100 yards, you'd be better off with perhaps a large sheet of that white corrugated plastic posterboard stuff, like they make campaign signs out of. You'll want it large enough so you can see where your shots are hitting, if they're off far enough. An 8-1/2x11" piece of paper is pretty small at 100 yards. To zero the rifle, you'll likely need to "walk" the shots to the bullseye.