MEC Super Sizer resizing tools - available for most gauges. The Super Sizer will eliminate problems caused by oversized shell, particularly magazine and feeding problems sometimes experienced by shooters who use semiautos in the field. To determine the BPI part number, simply add "130" to the beginning of the corresponding MEC part number. As an illustration, the Cap Plug, which has an MEC part number of 13X, would have a BPI part number of 13013X.