text: Bound's hubby here:\n\nKahr T9 is very much on target. The plastic plug you see IS Marlin's trademark "Bullseye". \n\nYou can actually puchase a sling swivel kit manufactured by Uncle Mike's of Oregon (see link). The forward swivel mount actually clamps onto the magazine tube, no drilling required! \n\nWhen you drill the stock for the coarse screw, be careful! Make sure the stock is braced, and preferrably using a drill press with a bit slightly smaller than the coarse thread screw, drill a hole about 2" from the heel of the butplate! Roll the coarse thread screw in a bar of soap to slightly lube the screw, and hand screw the coarse thread screw into the stock. \n\nIf you have reservations about possibly damaging your stock, take it to your gunsmith who will drill the hole for you. Some 'smiths will actually install the swivel mounts at no charge if you purchase the swivel mounts from him!\n\nGood luck!