"What did I do wrong with the reload?"
The most common problem folks create using the Lee collet die is they buckle the shoulder. If you did and it was not all that noticeable, it could certainly cause the round to stick in the chamber.
The buckle or bulge in the shoulder is much like having the crimp die set wrong. The most common cause is somebody tried the die out without brass in it. This can cause the collet to collapse inward and the mouth of the case can buckle or bulge the shoulder when the case enters the collet. It is very easy to fix. Just disassemble the die, and run a taper punch to spread the collet. This is covered on the Lee website.