A dangerous situation where a 20-gauge shotshell is inserted into the chamber of a 12-gauge shotgun followed by a 12-gauge shotshell. The 20-gauge shotshell represents a serious obstruction at the forcing cone when the 12-gauge shotshell is discharged. This obstruction will produce a ‘ringing’ of the barrel in this area at a minimum or a bursting of the barrel in this area.
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