Blockage between cap nipple and bore.

[FishDFly]

Since the viscosity of ATF and acetone is different, you will need to shake it multiple times for it to go in solution. If not, it will layer out in the jar.

 

[Grenadier1758]

Yes, ATF is the acronym for automatic transmission fluid. Note: ATF is a synthetic substitute for sperm whale oil.

 

[ADK Bigfoot]

Due to the heavy pitting in the bore, I would recommend using 1: sandpaper of varying grits, 2: a tight patch with polishing compound, and 3: fine oiled steel wool (in that order) run up and down that barrel from end to end MANY MANY times. Since it is a smooth bore, you can't hurt it doing this, and the more pits you can polish out the better it may load, shoot, and clean. Lots of elbow grease and long strokes is the key. I use a long wooden dowel spun in an electric drill. Just keep moving in and out from breech to bore and bore to breech. Clean thoroughly afterward. It should clean up nicely.

ADK Bigfoot