The reason I suspect a barrel full of gunk is many years ago I had a Renegade that did exactly the thing you're describing. At 25 yards I was fine. Then I made the mistake of taking it hunting and took an EASY shot at a little buck. I ended up gut shooting him. I knew the sight picture I had was perfect, the deer was not spooked and was unaware I was there,I never rushed the shot, the ignition was instant, and I had loaded it the way I always did. It had to be the rifle.

After spending the rest of the day and into the evening walking that deer down, I took thedeer andrifle back to the cabin where were staying. An old hunting friend of mine listened as I told the story of the great hunting disasterand tracking job and he commented that he thought my rifle barrel was filthy. I of course argued telling him I water bathed it every time and the patches came up clean. He then said that I needed to brush the barrel back to metal time to time and asked when I had done that last. I admitted the rifle was about 15 years old and I might have scrubbed it twice in my life.

We then made the boiling water bath and worked the barrel over with solvents, brushes, patches, you name it. The chunks of old bore butter and gunk that came out of the barrel shocked me. Two days later I shot at a target on a range at 100 yards and shot a little under a four inch group (as I remember)with the T/C peep sights on the rifle. That was the end of my use of bore butter by the way.