So now you have a massive flash hole in your plug. It needs a Savage type vent liner and a 5/32 flash channel. A flash HOLE that large is a primer rupture waiting to happen. Anything over a .036" hole and a breech plug is toast.

You even responded to the thread on how Ron does them. Process is the same for the old style TC hex head plug.
CVA Hex Breechplug Modification