Howdy
I guess I should chime in on this one.
I stopped completely disassembling my Black Powder revolvers to clean them a long, long time ago. Probably back in the 1980s.
Besides being a lot of extra work, there is the chance of loosing small parts, or cross threading screws.
I also learned a long, long time ago that if you clean with water, you have to get all the water out again. Leave some of the water down inside and you are asking for rust to happen.
I used to completely disassemble my Cap & Ball revolvers, and clean everything with hot water, just like everybody else does. Then to drive out the water before reassembling I would place everything in an oven heated to just above the boiling temperature of water. Hot drying the parts this way always resulted in flash rust.
Let's consider a couple of facts here that I don't think anybody has mentioned yet.
1. Black Powder fouling is not as corrosive as most shooters believe. In the old days, the combination of Black Powder fouling with corrosive primers made for corrosive fouling that could quickly cause rust. We don't use corrosive primers any more, and I believe most caps are non-corrosive these days too. The result is that Black Powder fouling is not as corrosive as most shooters believe. If you don't clean your BP revolver the same day you shot it, it is not going to disintegrate into a pile of rust over night.
2. I discovered a long time ago that if Black Powder fouling is soaked in oil, it looses its ability to suck moisture out of the air, which is the cause of most corrosion with Black Powder fouling. Yes BP fouling is extremely dry, and given the chance it will absorb water vapor from the air. Moist BP fouling in contact with steel is a good recipe to form iron oxide. But if the fouling is soaked in oil, that does not happen. Think of a dry sponge. Given the chance it absorbs lots of water. But if the sponge is already saturated with water, it cannot absorb any more. So if BP fouling is saturated with oil, it is like that saturated sponge and cannot absorb water vapor from the air.
I have been shooting Black Powder cartridges in my revolvers, rifles, and shotguns in CAS for close to twenty years now. Early on a friend clued me in to a water based BP solvent he called Super Juice. It is a 1/1/1 mixture of Murphy's Oil Soap, drugstore rubbing alcohol, and drugstore Hydrogen Per Oxide. Mixed together in equal proportions. I coined the term Murphy's Mix for this concoction a long time ago, and you will probably see mention of it if you go to the SASS Wire.
Let's go back for a moment to my statement that BP fouling soaked in oil cannot absorb moisture. Before I shoot any Black Powder in a firearm, I first 'set it up' for Black Powder shooting. I completely disassemble the piece, I remove all the oils and grease from everything with solvents, and then I relube everything with Ballistol before reassembling the firearm. That's it, I do this only once. Ballistol is a very BP fouling friendly lubricant, developed by the Germans in 1904 as a lubricant for firearms and a treatment for leather.
https://ballistol.com/about-us/
I used to remove the oils from my guns with a strong solvent like laquer thinner, but these days I use rubbing alcohol. Safer to use.
Here is a Colt Single Action Army, completely disassembled, ready to be relubed with Ballistol. Unlike most advice which says to use lubricants sparingly, because too much oil can attract attract dust, I slather the Ballistol on nice and heavy, so every square inch of the inside of the frame and all the parts has a nice, even coating of Ballistol. Attracting dust is not an issue.
This is an antique Smith and Wesson New Model Number Three. I have disassembled it as far as I care to, to ready it for Black Powder shooting. I have popped out the cylinder and removed the grips and hammer spring. I have removed the side plate and pulled out the hammer. I do not take these revolvers apart any further because they are quite tricky. Instead I use plenty of Q tips and rubbing alcohol to swab down every surface to remove all the old oils, then relubricate everything with Ballistol before putting it back together.
Here is the inside of the frame of a S&W New Model Number Three with the old oil dissolved away, ready to be coated with Ballistol. Notice I have not completely disassembled the gun. The trigger, trigger spring, and the rest of the lockwork are still inside. I did not want to drive out the pins to remove them. Plenty of rubbing alcohol with Q-Tips, followed by a coating of Ballistol does the job.
After preparing my firearms this way, they are ready to be shot with Black Powder.
Here are the ingredients of Murphy's Mix. I buy them in the local supermarket. I buy them in 32 ounce containers so when mixed together they will fit into an old, opaque 3 quart juice jug.
Now all of you guys who are sitting back and saying why come up with such a complicated concoction when hot water has been a good way to clean clean Black Powder for hundreds of years, I have a couple of answers for you. First of all, you don't have to heat this stuff, you can use it cold. Which means you can use it in the field, you don't have to go home to heat it up. I always clean my rifle at the car with Murphy's Mix before heading home. Cold, right out of the bottle.
But more important, unlike cleaning with water, you don't have to get all the water out again. What ever fouling has gotten down inside the mechanism of the gun, I just leave it there. It will not cause any rust. The alcohol is about 70% water, the rest is alcohol. The Per Oxide is about 94% water, the rest is Per Oxide. It is the water in these two ingredients that does the actual dissolving of the BP fouling. The Alcohol content helps the mixture evaporate quickly, and the Per Oxide adds a little fizz to help lift off stubborn fouling. When the alcohol, water, and Per Oxide evaporate away, the oil soap is left. The oil soap will coat everything inside with more oil. And there will be no rust.
Once a year or so I completely disassemble my BP firearms to clean away all the black, oily guck that has accumulated down inside. There is always plenty of black, oil guck. When I wipe it off, there is never any rust. Never.
Here is a Colt I took apart last year to clean out all the Black Oily guck. Notice there is plenty of it. There is no rust. The Ballistol and the Oil Soap prevented the fouling from absorbing any water vapor, so there is no rust. Been doing this for close to twenty years.
I seldom clean my guns the same day I shoot them. I'm just too tired after driving to a match, spending the day shooting, and then driving home again. I try to clean my guns during the week following a match. I have often gone much, much longer than a week. I will not tell you how long, but I did take TWO MONTHS to clean a pair of my New Model Number Threes after a match. Just plain lazy. Once they were clean, there was no rust any where. Remember what I said about BP fouling not being as corrosive with modern non-corrosive primers? No excuse for being that lazy, but them's the facts.
When I clean my Colts I remove the cylinder and the cylinder pin. I also pull the removable bushing out of the cylinder. I fill a cup with Murphy's Mix and dunk the cylinder in it. Then I use a bronze bore brush to scrub out the chambers. A few Q-Tips soaked in Murphy's Mix clean out the center hole. A bronze bristle brush scrubs off the outside and it is clean. I run a bore snake through each chamber to dry them out and set the cylinder aside. Next the Cylinder Bushing and the Cylinder Pin each get dunked in the cup of M-Mix and brushed off with a bristle brush. The bushing gets a 22 caliber bore snake dragged through it to dry it out. Set them aside. Next is the frame. A bunch of passes of a bronze bore brush through the bore cleans out all the fouling. A bore snake dragged through the bore wipes it clean. Then lots of scrubbing with bristle brushes on the cylinder window of the frame. Special attention to the corners where fouling tends to accumulate. I am always sure to use Q-Tips to work some M-Mix into the slot in the frame where the hand pokes through. I also dunk some down into the frame where the hammer slot is. This renews the oil down inside. That's it, the gun is now clean. Next, I relube everything a little bit. One cleaning patch soaked in Ballistol gets run through the bore and chambers, followed by a dry patch to mop up the excess. This leaves a light coating of Ballistol in the bore and chambers for next time. A few drops of Ballistol down inside with Q-Tips. A quick wipe down with a patch lightly soaked in Ballistol on everything else and I am done. Total elapsed time to clean two revolvers about 20 minutes if I don't get distracted.
Cleaning a rifle or shotgun is even easier since they are basically just tubes. With a cartridge such as 44-40, which expands well to seal the chamber almost all of the fouling stays in the bore. M-Mix, with bore brushes and and patches, a little bit of scrubbing around the carrier and bolt, drip some M-Mix into the frame by the hammer, and they are clean. Apply some Ballistol to the bore just like with a revolver.
I will tell you one other thing about cleaning up after Black Powder. Far less scrubbing is required than cleaning after Smokeless. The fouling is not as stubborn, as long as you used a soft BP compatible bullet lube. Use Smokeless Powder bullets with hard modern bullet lube and you will have much more work cleaning the hardened fouling out.
The other nice thing is there is never any leading with Black Powder. I don't know why, perhaps because BP burns so hot, but there is never any leading inside the chambers or bore.
Here is a photo of an Antique Merwin Hulbert and antique S&W New Model Number Three ready for cleaning after shooting with Black Powder. That is as far as I disassemble them. In fact I usually do not remove the grips. But I use a heck of a lot more Q-Tips than that.
Cleaning a Top Break S&W is a bit different than cleaning a Colt. Lots of M-Mix down inside the hollow cylinder arbor to remove any fouling. And a bronze bristle brush to remove visible foulinig.
A dirty Top Break recoil shield before cleaning.
The same revolver after cleaning.
Just for fun, here is my cleaning kit. Lots of bore brushes and bristle brushes. Lots of Q-Tips and several bore snakes of different sizes. A small squirt bottle of Ballistol. The larger bottle has Murphy's Mix in it.
One other thing:
You guys who like to clean your guns in the dishwasher, think about the lead you are exposing your family to when you use the same dishwasher that you clean your family's dishes in.