The subtle radius of each shell holder mouth ensures smooth and reliable functioning. The retainer spring is designed to stay in place when inserting cases into the shell plate. Shell plates for Lock-N-Load AP and Pro-Jector are available to fit most calibers. Each shell plate will also hold additional calibers with the same case head dimensions. Current shell plates are designed to fit Lock-N-Load AP (both EZ-Ject and wire ejector models) and Pro-Jector presses Shell plate #10 fits: 357 Sig 40 S&W 10mm Auto