The gun may just be on the small side of the spec. End of chamber diameter spec for a 16ga is .742 to .732. The end of my Brownells plug gage is .735. When chamber reamers got dull they sharpened them each sharpening made them smaller. Check the chamber length with a barrel wall thickness gauge. The indicator will change direction at the end of the chamber. My 12ga Brownells plug told me an LC Smith had 2in chambers. BWT showed it to be 2 3/4in

Mark

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