I don't recommend Lee FCDs for new reloaders because I saw a new reloader blow a Colt DE (10mm) to bits, partly because of the FCD.
He was overcrimping to the point where the case mouth was pushed completely into the (now deformed) bullet. The resulting bulge wouldn't let his rounds chamber, so someone recommended the FCD. He tried it, and it "worked". His horribly made ammo would now chamber, but the rounds were headspacing on the extractor rather than the case mouth.
After experiencing light strikes, he switched to the longer LR primers (his idea after reading on the internet) and thought he solved the problem. I was a couple of lanes away when his gun blew up. He was OK (a couple of small cuts on hs face). When I found the slide, the extractor hook was broken off.
Here's what I figure happened:
The rounds were headspacing on the extractor and the extractor broke off on the second-to-last round. The last round headspaced when the middle of his crimp hit the lands, with the case mouth into the rifling. The bullet was stuck, and the pressure blew up the round.
I looked at his remaining ammo and saw the horrendous crimp. I asked him, "Why did you crimp so much? He said, "It didn't feel like I was doing anything, so I tightened the die down until I could 'feel' the crimp."
He was reloading on a Rockchucker with a separate crimp die. You won't "feel" anything - you can let go and just drop the handle on a Rockchucker and it'll complete the crimp on a 10mm. I felt the high primer when I was examining his ammo and he told me about the LR primers then. I offered to let him take my class for free. He said he'd do it if he decided he was going to keep reloading. I never heard from the guy. I hope he sticks to factory ammo.