Wonko, you came to our rescue. Not only are the implications of wierd choke configurations a fallacy (a politically correct term for bullshit), but we have measured enough Lefever bores to find that the "tapered bore" story is bogus. We have found a few "tapered bores" out there, but none of them seem to come from the factories. Lefever made "tapered chokes" and the tapered bore thing is a matter of misunderstood rhetoric. Please correct me if I am wrong. By the way, this is a great thread, as some posters have mentioned.