Looking closely at the picture of the "cleaned" barrel, it appears to me that there's a lot of crud in the chamber starting just past the "shiny" area of the chamber beyond the feed ramp.

The crud in the chamber needs to be cleaned with something that cuts carbon and powder deposits-I'd recommend soaking the inside of the barrel with some M-Pro 7 gun cleaner as it does a fantastic job at cutting through that kind of junk. Then give it a really good scrubbing with a bronze brush, repeating as necessary.

The chambers of my pistols look nice and shiny and it's easy to get them that way without chance of hurting anything. Get an appropriate caliber bore mop and some Flitz. Load up the bore mop with Flitz and go to work on the inside of the barrel, focusing on the chamber. I use Flitz through the entire barrel because I've found that it makes cleaning it easier-junk doesn't stick as well to the inside of it. Flitz is an extremely fine polish and after 30 years of using it-haven't hurt a thing and always made things better.

I've chucked a bore mop up in my variable speed hand drill and used it in barrel chambers with rough finishes and it's always improved things noticeably. Makes clean-up a snap.

Edit: looked at the pictures again and it looks to me like there's a significant amount of crud in the chamber. Get it cleaned down to bare metal and see how it shoots. Bet it'll be just fine.