Chamber length of a shotgun is not determined by the length of the "Loaded" shell but the length it unfolds to after firing. The fired length of most nominal 2 3/4" shells will fall a bit short of 2.75", but nowhere near that 2.3"-2.4". It is worth noting though that until fairly recent times SAAMI specs for the 2 3/4" 12 gauge chamber allowed for a minimum length from breech to cone of 2.6136". Thus any nominal 2 3/4" shell would upon firing lap up intp the cone of a chamber cut to the minimum specs
"No" shotshell should "Ever" be fired in a chamber in which the "loaded" shell has to be forced into the cone.
