Gunk in cylinder

[huntswithdogs]

I've been having some issues with some of my shells rubbing on the frame when shooting the ACP cylinder in my flattop. I thought I had the OAL wrong until it started doing with factory stuff yesterday. On close inspection last nite while cleaning it, I found some kind of gunk in 4 of the cylinder holes. I'm talking baked on, hard stuff. I tried soaking it with Hoppes and letting it set for an hour, No dice. I then tried some foam stuff and it didn't work. I tried the choreboy that I use to get any lead out of my barrel but I couldn't get it fitted in right to get at it. I may try the blade of a small pocketknife tonite. Can bullet lube flow backwards when firing? I don't think it's powder because one of the 2 cleaners woulda/shoulda done something to it. I don't think it's lead.
Oh this stuff is in the part of the chamber that the shell goes in, not the very front.
Ya'll got any thoughts or ideas?

HWD

[Graybeard]

Use a 45 caliber bronze or brass bore brush in an electric drill. Should remove it fairly quickly with no harm to cylinder.

[huntswithdogs]

Thanks GB.
I used a small flatblade screw driver to scrap it a bit to see what it was. It looked like bullet lube. My  brush is about wore out so I wrapped some choreboy around it, chucked it in my drill and went at it. Now I have 6 clean, shiney chambers. I reckon this came from my first attempts at loading the ACP cartridges. Low pressures and not getting my crimp tight enough was probably what caused it. I'll have to keep an eye on it.

HWD