Pistol cases tend not to lengthen, but that can depend on the crimp applied and the velocity they are shot at. In my pistol days I found that automatic rounds tend to shorten rather than lengthen but revolver rounds did lengthen a bit, never so much that they went over the maximum length. How ever the cases did need trimming to keep them all the same length and keep the case mouths square, this is important for even boolit retention. Same case length is also critical in revolver, or rifle, rounds that use a roll crimp, if the cases are different lengths then the roll crimp will not be consistent and you could get bulging.hakeswill wrote: I have been told that I wont ever need to trim the cases reloading pistol cartridges is this correct? I dont need to buy a case trimmer or deburring tool?
I always trim my brass when I first get it to ensure consistent length and evenness, then monitor case condition from there on. The Lee trimmer is cheap and effective even although it will only trim to a fixed length.