Grizly....
The annular rings are machining marks and the inside of the die could stand to be more shiny (smooth).
To that end, the felt bobs that I'm referring to can be sourced from any store that carries Dremel Moto Tool accessories, in fact, the mandrel that will chuck in a moto tool (that has a screw thread on the end to screw on the bob should be in the kit with the bobs. I think the whole kit with a bunch of other stuff is about 5 bucks, I believe Lowes, Menards and Ace have them....
I just happen to get my bobs (and lapping compound) from MSC because I have an account there and I use a pencil dir grinder but any small drill will work so long as it spins fairly rapidly.,,,, and the jaws on the chuck are tapered enough to allow the bob/mandrel to travel the full length of the inside of the die....
You'll have to get Clover Lapping Compound from a retailer that carries machine tool stuff. Clover is a Permatex product so you might be able to find it online, maybe Amazon.com I buy mine in small metal cans but I believe it comes in squeeze tubes as well. It's a very,very fine abrasive in a grease base.
You'll be able to run the bob all the way up to the shoulder in the die and because it will flex (it's soft), it will polish the shoulder too. Just size the bob to fit snugly in the bore of the die. They come in an assortment in the accessory pack.
The lapping compound won't change the dimensional aspects of the die, but it will smooth it. That should help the brass release.
Apply a tiny bit of compound to the outside of the bob and put it in the bore and use an in and out motion, continuously moving to establish a cross hatch pattern, like you'd hone a cylinder in an engine
If you are getting scratches vertically on the case when sizing, and the cases are clean, there may be a burr delevloping from earlier stuck cases. The lapping compound will remove it. They don't really get 'stuck' in that sense, what happens is they sieze (weld) to the die wall and when you pull it (brass), it leaves behind a tiny bit of brass thats actually pressure welded to the wall.... You put a tremendous amount of pressure on the brass and die wall when you resize, especially magnum cases.
My dies have a mirror finish inside and I ocassionally run a bob up the hole as preventive maintenance.
Finally, like the previous post stated, if you use spray on release compound, let it dry before sizing. I use Hornady One-Shot in the ziplock bag method. 50 cases in a zip lock bag, a couple second shot of One shot, zip the top and make bread for a minute, then open the bag and let the cases air out for 15 minutes of so before resizing to allow the stuff to dry.
Lapping compound has many uses, from polishing jewelry to removing the fog on plastic headlight lenses.....
I would imagine a stuck case is a real PITA.