I crimp, so that shock, vibration, dropping

, helps keep the bullet where it should be when hunting. If you have a lever action or want to load any for a lever action it's a necessity. Also, the FCD post sizes to make sure that if you missed a re-size on a case, it will still typically chamber. I also get better accuracy in my .45-70 BC and .45 colt BC with the crimp. If it's moist, I think it tends to help avoid bleed, especially if you don't lube the seam with liquid alox etc. I know some do well without it though, so that's up to the individual.

I find that with .45 ACP I cannot seem to have issues chambering a few bullets here and there if I don't also. I think it's the slight bulges in the case from the base of the bullet entering. I have a Blackhawk chambered in .45 COLT/.45 ACP and the acp cylinder is SUPER tight tolerance. Without FCD, I get about 20% that won't chamber in it properly and they hang up the cylinder often when they do go in but not fully. I think it's good also, if shooting many lower power loads, ie. my .45-70 Round ball loads.
