If that worn plug is modified, the eroded flash hole will be replaced with a vent liner which will have a flash hole size the same as the factory new breech plug. So, essentially the plug will be 'reborn'.

Another good result is, the vent can be removed each time the plug is cleaned; making cleaning the plug so very very easy.

If the vent is installed correctly, the plug will become quite BH friendly. The plug with a vent installed will be as good igniting BH, as the new made for BH plugs now sold by CVA.

Instructions for how to modify the cva plug to successfully burn BH can be found here.