My money is on jamming the bullet or case neck tension. This sounds more like you jammed the bullet. If you had a carbon ring big enough to sick your bullet on ejection, you would of been crying a lot sooner on the accuracy of your rifle before this happened. I don't recommend sizing case necks using bushings anyway. But that's just me, Its easy to screw the neck tension up with bushings. Been there done that. If you can get your hands on a borescope, it's the only thing that going to show you if you have a carbon ring.. Just so happens I cleaning my Howa 1500, it has about 500 rds through it. When I deep clean my rifles I check up with a $50.00 Teslong borescope from amazon. A must have tool if your serious about shooting, or OCD about the state of you barrel. Here's a pick of a carbon ring that isn't causing a problem yet in my 1500. Lets us know what you find out about your issue and how you solved it. Good luck. The bottom pic is after about 30 minutes of scrubbing with Hoppes #9 bore cleaner.