Lee FCD isn't really needed if all other adjustments are correct.
True---most of the time. Mixed brass, dirty chambers, minimum spec chambers, all factor in. I loaded tens of thousands of 45acp before there was a FCD. I learned quickly to chamber check each loaded round. There were always a small percentage of rounds that wouldn't chamber in one or more of my pistols. Enter the FCD. When I got one in .45acp, I ran a bucket full of my rejected rounds through the die, and WOW! Now they chamber in all my pistols! Since then, I use the FCD for all my pistol calibers as well as the 5.56. I load range brass for my pistol calibers. I won't load without the FCD.
Savage