I also have a new 204 barrel for my Encore! I haven't fired it yet either!
I would suppose that the reason the cartridge rubs so much is due to the fact it has hardly any taper to it, so when the shoulder is inserted into the chamber it has to rub a little.
Got my curiosity up, so I had to go get my rifle and try a cartridge in it! It didn't rub until the cartridge was about 3/4 of the way into the chamber and it didn't leave any brass shavings on the chamber or the extractor!
Your problem may go away with use! Sometimes when things are manufactured, they have sharp "tooling" edges!
If it is real severe, I'd recommend that you contact T/C!