Back in the 80s when I was in stool shooting, we just used paper towel roll one enough for a tight fit into the neck, lit them off in a 55 gallon drum over at TJ's shop. He will make the first pass in turning necks, then fire form them again in the drum before making the final turning. Last step is fine tuning the necks with steel wool.
I never asked whether there were any media in the drum, but it sure made one hell of a noise muffler.
I never asked whether there were any media in the drum, but it sure made one hell of a noise muffler.