I was hoping you would respond, Larry. As to coning on the outside, the White Lightening vents are quite thin walled between the inside cone and the outside flat. of course, this depends on how much is filed off to make it flush, which is directly effected by how deeply one countersinks the vent in the barrel. When m rifle is loaded, I can see powder in the vent's inside cone, from the outside. If I was to cone the outsdie, it woudl be way too thin and burn out prematurely.