back from vacation now...
I never did put in a vent liner. I simply had a .200 hole put in. Ya, I know, not the best way to do it, I don't need a lecture, but it was fast and didn't cost me anything.
In my mortar they EDM'ed it. In the carronade they put it in a big machine and drilled it. If it becomes a problem later, I can have it drilled/tapped and install a liner.
I assume the same people could drill and tap it for a liner for you, but you would have to give them all the details about how you want it done. I have no idea how much they would charge. They did what I needed done for free in return for letting the whole machine shop hunt out behind my house.
The machine shop is in Westfield, Ma, and they won't freak out if you call and start talking cannons as they have gotten over that already ;-)
If you want contact info, let me know and I'll send it to you.
Rick
