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PetahW · May 10, 2011, 05:06 PM

FWIW, just because the chamber(s) will accept an unfired 3" shotshell doesn't mean they're long enough for the fired shell, since shotgun barrels chambered for 2-3/4" shells (fired length) are long enough to accept a 3" (fired length) unfired shell.

Dismount the barrels, and check for the chamber marking(s) in millimeters, on each barrel, which should be "12/65" (2-1/2"), "12/70" (2-3/4"). or "12/76" (3").

The actual firing of ANY shell, that's too long for the actual chambering (regardless of length/gauge) will severely raise pressures as the shot column has to force it's way past the throat area, that should be wide open, but is now restricted by the open end/crimp of the too-long shell.

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May 10, 2011, 05:06 PM	#4
PetahW Senior Member Join Date: September 19, 2008 Posts: 4,678	FWIW, just because the chamber(s) will accept an unfired 3" shotshell doesn't mean they're long enough for the fired shell, since shotgun barrels chambered for 2-3/4" shells (fired length) are long enough to accept a 3" (fired length) unfired shell. Dismount the barrels, and check for the chamber marking(s) in millimeters, on each barrel, which should be "12/65" (2-1/2"), "12/70" (2-3/4"). or "12/76" (3"). The actual firing of ANY shell, that's too long for the actual chambering (regardless of length/gauge) will severely raise pressures as the shot column has to force it's way past the throat area, that should be wide open, but is now restricted by the open end/crimp of the too-long shell. . Last edited by PetahW; May 10, 2011 at 05:17 PM.