the M type expanding dies will change your life. I also once read a review on seating dies and according to the reviewer both the Redding competition seater and the Forster micrometer seaters actually corrected run out on bullets that had been seated with runout (crooked) previously. I can tell you that since I started using a combination of M style expanders and those seating dies, my reloaded handgun ammo has been much more accurate. I know that from using a handgun benchrest for testing to verify that it wasnt just me being a terrible marksman. I learned this when I started reloading 500 magnum and was disappointed by how lousy my reloads were shooting. Then I was at my bench one day and accidentally knocked a loaded round over and watched it roll across the bench top, the runout was obvious as it rolled, and severe. I was using lee dies at the time, started researching and made the switch based on the info I found and all the sudden my 500 was a tack driver. I saw it on some 223 I Ioaded not long after, same thing; the Redding competition seater fixed it. on a side note the lee carbide sizing die also sized my 500 mag brass smaller than it needed to be and when I switched to the Redding I was amazed by how much easier it was to size them, and they still chambered and neck tention was just fine.