From what I understand, opening the choke will not alter the pressure as the pressure is already greatly reduced by the time it reaches the muzzle. Most of the pressure occurs inside the chamber and just in front of it. See my current post regarding chamber reducers as much of this is covered. I agree, if the bulge happened midway, it was most likely caused by an obstruction, like maybe a stuck wad.

Last edited by gunsaholic; 11/21/11 02:15 PM.