After firing my 629-4 a hundred rounds I wanted to give it a good cleaning.
My reloads are 200gr RN powder coated in front of 14.7gr of BlueDot.

My cleaning method is as follows:
Three patches wet with Mercury Quicksilver Power Tune (a carbon remover).
Five or six strokes with a brass brush.
Patch until clean and dry.
Two wet patches with Kroil.
Five or six strokes with a clean brass brush.
Patch until clean and dry, repeat if necessary.

The barrel cleaned up easily and so did the forcing cones in the cylinder but the black residue on the front of the cylinder is another story.
Can anyone give me a place to start?
Thanks!

I used to use a lead away cloth,but found mothers mag polish was easier.You can get it at Walmart and auto parts stores

Yeah.. shoot another 100 and forget about it.

There are two components to the color visible on the front of a stainless cylinder after firing:
1. Powder/ lead residue which can be removed with a brass toothbrush and proper solvent.
2. A microscopic carburized layer that is actually partway into the steel itself. This layer does no harm, and is self-limiting. You can either just leave it alone, or remove it with something like a lead removal cloth, abrasive paste, or de-carburizing solvent.

Personally, I leave it alone, because it does no harm and comes right back at the next shot if you do remove it. I kid some friends who scrub theirs off at every shoot, taking an hour to clean a revolver, while I clean mine in 10 min, and I shoot tens of thousands of revolver ammo yearly.

Your choice.

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Science plus Art

Yeah, you can forget about it, but I can't. So I use a commonly available product called Brasso. Put some on a swatch and watch it disappear. It is an abrasive and it does have ammonia as an ingredient so I only use it on the front face of the cylinder.

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I'm gonna grow fins.

Like arjay said, the lead removing cloth works well. With the cylinder in your hand, your done in about a minute.

0000 steel wool and Kroil should take care of it.

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Life Member NRA
Acts 2:38-39

Anything that will fully remove the carbon fouling from the face of the cylinder will be removing microns of metal -- your call if you feel comfortable doing that after every cleaning just to make it shiny. I don't.

Also, search; here's a thread on the same subject just a few down from this one: How do you remove cylinder ring burns on stainless guns?

Exactly. And consider avoiding the abrasives - some report a cumulative effect over time. It is a slight harmless discoloration on the front of the cylinder. And, NO ONE NOTICES. EVER.

I use Hoppes and a copper brush. Being softer than steel it shouldn't do any damage, but it does remove the residue.