Chamber Length
With respect to Mr Margiotta's question, and my post of a few days ago, his measurement may reflect chamber taper, and not chamber length.
I have attached page 17 of the current SAAMI ANSI standard. Note that the length specification for modern 12 ga cases is 2.76 - .100 inches, tolerance - .250. Remington and Winchester cases measure 2.66. This is 1/32 inch over 2 5/8, probably well within tolerances for paper and plastic. Also note the plus tolerance is zero.
I would like to call your attention to the modern chamber and forcing cone drawing below the case drawing. The modern 5 degree forcing cone makes the Parker forcing cone look like a bore obstruction by comparison. Although modern ammunition seems trivially longer, an extra 1/8 of chamber length is a great safety factor in the case of a case separation or other shell failure.
Best, Austin
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