Reloading 9mm: Comparing two sizing dies

A long while back I was writing about how I made a shim to keep cases from hitting my sizing die.Let me take a step back though to explain what this thing does. For this I need to go back to the gun itself. When you pull the trigger a fire a round an interesting thing happens in the chamber -- the case expands. Why? Simple: brass is a very soft metal. Its job isn't to hold in the pressure of the gun powder. It serves to purposes: hold the un-fired cartridge together and as a seal in the firing process.The first of these is obvious to anyone that has ever picked up a round of ammunition, the second is less intuitive. While the tolerances in modern firearms are very tight, there's some huge tolerances in ammunition. Some of the specs allow for a hundredth of an inch in either direction! Yes, I know that sounds small, but it's actually really big in this case. Even if you could make it a perfect fit, you wouldn't want to; the moment a piece of dirt or grit got in the chamber you wouldn't be able to feed another round in.The upshot is the chamber (where the cartridge sits at the breech-end of the barrel) is bigger than the case. When you pull the trigger the primer ignites the powder and that starts to push the bullet out of the case. At the same time it causes the case to expand to seal the chamber from the hot gasses that are being produced. If this didn't happen, you would have a lot of blow-back of gasses since the burning powder would try to get around the case and back out the breech-end of the gun -- into your face!So, at the end of that process you have a case that was bigger than it started. So big in fact that it might not chamber a second time. Certainly it'll be too big to hold another bullet. What to do: resize the case to the original size! That is precisely what this die does.Well, what was going on is that the Redding die kept jamming things up. The case mouth would hit the die instead of going in and resizing. Perhaps it's stacking tolerances with the press, shell plate, and die, but regardless the reason it would hang up perhaps a third of the time.So I decided to try to get another die. I picked up a Lee since they are pretty cheap. Sometimes people seem to avoid them because they are cheap... but I've not had any real bad luck with them. Above the Lee die is on the left and the Redding is on the right.What you can see when looking into the business-end of the dis is that the Lee has a slight chamfer on the edge that the Redding lacks. This is both good and bad. Good since in the 500 rounds I made today I had no hangups. Bad because it doesn't size the case down as far. But sizing it down that far isn't strictly needed anyway since the case head doesn't really grow while things are being fired.So... there you have it. A $21 solution to an irksome problem.