I picked up this 45-70, Uberti 1885 High Wall, DST, was supposed to be un-fired and it looked to be.  Excellent, new condition, box, papers, etc.
Made up some loads similar to those used in my other 45-70's and went to the range.  Rifle shot very good; had some good groups at 100 yds.  I noticed most all the fired cases were difficult to extract.  Some came out fine, but most required a light prying to be removed. My first thought was a dirty chamber or the fact this brass had been used in another rifle, although it had been full-case sized.
After I returned home, I cleaned the chamber and tried to re-insert some of the fired cases. All would go in except for the last half inch that required a stout push then they would "snap" into place.  Extraction required prying.
I noticed the cases were slightly bulged about 3/8" above the base, but not completely around; maybe 1/4 to 1/3 the circumference. Using a bright light, I scoped the chamber and could see a slight shadow at the top. Looking at the slight off-set of the primer indent, I could tell all the bulging was occurring at the same spot.

My question is ; is this chamber "ringing"?  I assumed when ringing occurred it would be all around and not just partially. Further, the bulge is only 3/8" from the rear face of the cartridge case and this seems to far to the rear.

I was shooting 490 gr cast from 20:1 alloy. 33 gr of Black Horn 209 fired by Federal 215 Match primers. Starline Brass. 0.60 veg wad under the bullet and no air space. Velocity on this load is just under 1200 FPS.  I have fired hundreds of this load in other rifles with no issues.

So, any opinions?  Could this be a manufacturing defect?  Any thoughts on a fix? 

Are you SURE? that it is unfired. Many years ago a friend had a M1885 re-barreled to 38-55. He loaded ammo with new brass and went to the Range to shoot. I got there about 15 minutes behind him and he was prying the empty brass from the ChamberHe said it did that on his first shot. I had looked the Rifle over the day before and saw no sign of a Rung chamber. But there was now, easily visible. I asked about his load. A Hudson bullet cast hard, I think it was Linotype and fairly large
in weight, 330 Grs. with a stiff charge of Fast burning powder. 
This was a Barrel by a noted barrel maker of the time using one of the Soft free Machining materials that was popular at the time. I believed then and still do that he Bulged that Chamber with his first shot because he said the Shell came out hard with the first shot. Was a shame as it was a #4 Full Octagon with a Rifled False Muzzle and a Bullet starter with a Loading Rod to seat the Bullet to the right place in the Barrel.
It also had/has a really bright and shiny beautiful Bore. I still have that Barrel as I traded it from him. Had planned to re-chamber it and salvage it. But later heard of others having the same problem. the Material just may have been too soft. Is your Barrel marked "For Black Powder Only" I have since heard of others like this. HTH regards, FITZ.

I would send the rifle back to the maker. A raised area rather than a raised ring tells me the barrel is suspect rather than a abusive user.

Quote:

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.