What is a vent liner?

[BlackPowderGuy (AJHS)]

I see that SSK sells a breech plug for CVA inlines that includes a replacable vent liner. What is a vent liner? What is it's purpose? Does that blackhorn breech plug that CVA sells include one?

 

[sabotloader]

The removable vent liner makes it possible to replace a worn flash hole in the powder end of the breech plug without the necessity of replacing the entire breech plug.

This picture shows the installation of a vent liner in these two older plugs.

The vent liner will also normally last much longer than the typical Flash Hole in a breech plug.

 

[HC]

? Does that blackhorn breech plug that CVA sells include one?

No, cva plugs have to be machined to accept a ventliner.