I had thought that I was getting some flaking of the nickel, but a closer inspection revealed what looks like a slight buildup of lead on the end of the cylinder, between each flute.

The gun was drilled and tapped for a scope, though it was removed and the open sights are back on. One of the empty screw holes on the top of the frame (covered on top by the rear sight) is directly above the lead spots. Not sure if that makes any difference.

The gun shoots flawlessly with exceptional accuracy.

My question: Is there a solvent that will help remove the lead without harming the nickel? A finger nail does not seem to do the trick.

PS - the inside of the chambers and the barrel look fine.

Regardless of whether the gun was factory D&T (round end rear sight) or after-market, get some plug screws and plug those holes. You are also getting high pressure gasses blown through the holes and being deposited under the rear sight, which can cause other problems eventually.

What you are seeing is a result of powder gasses and the associated Carbon, Graphite and Lead carried with them being reflected by the hole resulting in a distinctly round spot of fouling on the outside of the cylinder directly under the front hole. All revolvers will foul in this area, but without the hole the spot will be more fan-shaped.

Don't get too concerned about cleaning this, it will just come back every time you shoot the gun, and it causes no harm unless you get over-enthusiastic about cleaning it. Fine Bronze Wool with a good solvent or CLP type oil will do well, just don't work too hard at getting it perfectly clean. Nickel is softer than bluing believe it or not! If it were a blue gun I would recommend 4-ought steel wool, but not on Nickel.

This is one area that a very find polish like Simichrome, Mother's, or similar can be useful, but ALL polishes are abrasive to a degree, that's why they work, so don't over do or use too often. Even toothpaste could be used.

Thanks for the tips. I'll get some bronze wool and some set screws.

Just looking for a solvent to help it along a bit. A search located "Shooter's Choice Lead Remover". Will that harm the nickel?

Pro shooters taught me the best solvent for dissolving lead is a 50-50 mix of white vinegar and hydrogen peroxide. It worked great on my compensators. I don't guarantee it is safe for nickel.

One thing I use for cleaning cylinder tubes is a .40 NYLON bore brush on a 3" cleaning rod and a hand drill. Dip the brush in chrome polish or suitable cleaning material and spin inside the tubes. In stubborn cases I cut a thin strip off a scotchbrite pad and wrap it onto the brush.

Flitz and elbow grease will do it.

The finest polish I know of these days is the polishing compound they label as "clearcoat safe". That stuff was about as abrasive as cottage cheese.

Wow! I guess so. Yes, it took a litle rubbing, but not really that bad. My cylinder is now 100%. It even shined it up. I used the black spot on the cloth to lightly go over the rest if the gun and it looks like new now.

Thanks for the tip.