I have also found increased accuracy with the lee crimp die in some cases. I have a ruger m77 in .300 win mag that has a throat a bit longer than my magazine. I found that when using heavy charges of really slow ball powder someextra resistanceie. seating to the lands or inmy case a heavy crimp, did increase accuracy and lower standard deviation.I have even seen the crimp die decrease run-out. Not by much, maybe a couple of thousandths.