what the answers on your other thread with the same question wasn't good enough?
http://smith-wessonforum.com/reloading/125414-why-case-cannelures.html
http://thefiringline.com/forums/showthread.php?t=288737
http://forums.1911forum.com/showthread.php?t=179718
Hey I can see why he's still looking for a definitive answer,Those threads all appear to have guys that are not sure, but want to be the keyboard cowboy and answer the question.Let me know when you find a credible answer?



























