Hello, Is there any difference between plastic hulls and paper hulls regarding chamber length. Thanks to info on this site(and Brophy's book) I believe my 1915 featherweight to be chambered 2 3/4". During a recent telephone conversation with a gunsmith, I was informed that my gun was 2 9/16 and that modern plastic hulls(crimped plastic vs. rolled paper) were creating excess pressure. His suggestion was to lengthen chambers and forcing cones( I'm using low pressure vintager shells) Is there anything to his rolled paper vs. crimped plastic statement, or are the 2 3/4" 6000 psi plastic suitable for my sweet elsie? I have just recently joined your fine organization after having lurked around your site for some time. Thank You for everything I have learned here. DW