Other than Bell not much has been done with pressure in modern shells> I believe his work on shooting 2 3/4" shells in 2 1/2" chambers and lack of supposed increse in pressure.Just wondering if anyone has pushed it to the 3" into 2 3/4" to see if the same holds true.I am talking safe loads like the AA Feathers in the first case but wonder if the effect is the same shooting the later if shell pressures are about the same at the start.The old paper roll crimped shells are thicker going into the forceing cone so I don't think plastic or paper make much difference in the whole.Paper does smell better.
