Quote:...was supposed to be un-fired and it looked to be. Excellent, new condition, box, papers, etc.
So it is not a NEW IN THE BOX - Used!
* Look at the front of the hammer - full blue = unfired, missing bluing = fired
* Half of the cartridge won't chamber ... look at the bullet nose to see any scrapes or land engraving. If Yes, your COL is too long
* Take a Magic Marker and run a couple of fat lines down the case on opposite sides. Chamber & extract a round, look at the lines to see if they were scraped. If Yes - an issue point
* Were your cases full length sized that you used for your reloads. If not, do so and make sure the case web is sized. Then chamber a unloaded case with the Magic Marker lines and see what you have
Then get your bore light out and take a look in the chamber. If can't determine a ring - make a chamber cast and measure it
I'm an optimist guessing there is no ring - the COL and or cases are the issue.