Well, Mark, the answer to your question, "can I shoot 2 3/4" cartridges in a short chamber?" seems to have been answered! First memorize the SAAMI report, then fire your gun remotely while its hanging from a rope, get a degree in physics and mechanical engineering, buy some gauges to test stress, send your loads off to an independent lab to have them evaluated, then fire it from the space shuttle, with the tailgate down, and most important DONT listen to any one who who cant confound you with equations and datums...You are on your own, Pal, I got lost a long time ago...