If straight walled cases like the 38-55, 375 win. 444 marlin, etc. are straight walled but have a slight taper to aid feeding. Then the characteristics of the boolit which are designed usually without a taper, (straight driving bands or at least after sizing). Then seat the boolit in the case and crimp for tubular or not crimp for single shot. The boolit wouldn't be touching inside brass at the base of the boolit, whether GS or PB, correct? Would this scenario allow for cocking or the boolit, distortion on ignition, gas cutting on the drivings bands, whatever else (disrupting lube characteristics), etc.? Which would be detrimental to accuracy and leading. Take for example the 38-55. If from the web to .072 (I am assuming for crimping)before the case mouth is 1.813 inches with a taper of from the web to that .072 point, .419 to .394, a total of .025 taper. Now if you seat a 250 gr boolit in the case it would take up about .600 of case, or about 1/3rd of the case capacity. One third the taper of the case would be about .008. Even with a .376 sized boolit. that leaves darn near .004 gap between the GC or PB and the inside of the case wall. Do you see what I am getting at? I was just pondering a re-bore and chamber. Then noticed these dimensions while looking at cartridge drawings. Any thoughts, comments, or similar threads on the subject would be greatly appreciated. Thanx Should be in the CB, favorite cartridge forum