2-3/4" vs 3" loads, specifically

[2A2Dend]

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[afsgtpapa]

1/4" by my ruler. Seriously - one should not fire a 3" shell in a 2 3/4" chamber as there is the danger of over-pressure. Should one compare and read the boxes or containers the shells came in, one should be able to see the differences between the shells: different amounts of powder, shot weights, velocity, etc. Not labelled might be the different primers, shot cups, or powder used. Personally - when hunting upland birds [Chukar, Quail, & Pheasant], I prefer using 3" shells in both 12ga and 20ga.