Dean, I don't know if the swell was done from the breech or muzzle ends but it's long been described as a way to "normalize" the bare shot charge before starting into the choke. It's not as pronounced as jug choking. The earliest references to the swell I've seen were by Askins and Sweeley in the early 1920's as they experimented with borings and chokes for max long range pattern efficiencies, that was prior to the advent of the Super-Fox which was largely based on their work. What I wonder about now is what effect, if any, the swell has on performance with plastic shotcups. One of these days I'll do some comparative long range patterning with bare shot and shotcups to check for myself. Actually I had planned to do that in part for a DGJ article and that's why it slipped to the back burner when the editors pulled the plug. I've seen these swells on a few Foxes, Parkers, Winchester M12's, M21's and 101's.
|