I use a .375 H&H case. Sharpen the case mouth with your deburring tool & lube with petroleum jelly. Twist the case (I glued the case into a small block of wood) & don't apply too much pressure.

To hold the plug in the pad I use small amount of Pliobond or Barges cement.

To me, this looks much neater than cutting an x in the pad face or putting an unplugged hole in the pad if we are talking non leather covered pads & allows easy removal & replacement of the pad w/o buggering up the pad face.