I have an extensive chemistry background, I am not speculating. The ingredients of concern are salts. They are easily dissolved in water. Think about it, if you had a dried salty mess in the kitchen, would you use pee?, ammonia solution?, oil?, or water to clean it up? Water right? The fouling does not consist of acids that need to be neutralized. Any weak acids, like sulfurous, will be flushed out by water. Pee, ammonia solution and such only works because they're mostly water. Urea and ammonia are not good to put on steel. They will promote rust too. People make this much more complicated than it needs to be.
BTW, Yes, I have shot lots of corrosive high power ammo. I bought and shot, cases of 8mm and 303 corrosive ammo. It is not a big deal. No magic involved. Thoroughly flushing the barrel with water and then cleaning as usual, it works perfectly. I never had a speck of rust in any rifle from corrosive ammo. Just plain old water, really.
The problem comes when water is avoided as a cleaning agent. Some think that water is bad. They get nervous abut putting water in their rifle. They can 't say why but it give them the "willies". Actually, water is free and is the most effective solvent. There is nothing better.
Corrosive ammo vs Pyrodex.
The ammo you comment on was corrosive because the primers used a small amount of a chlorate or perchlorate. In the case of Pyrodex you are looking at 17 parts of potassium perchlorate as part of the oxidizer system.
During powder combustion the potassium perchlorate simply liberates the oxygen leaving minute crystals of potassium chloride scattered over the barrels interior surfaces. Under the right conditions these minute crystals will form electrolytic corrosion cell sites and cause pit corrosion in the surfaces of the bore.
The basic concept behind Pyrodex is the use of sodium benzoate as the "fuel". The amount of charcoal in Pyrodex is so small as to be meaningless in actual powder combustion. But the combustion reaction rates are so slow with the sodium benzoate that a good healthy slug of potassium perchlorate is needed to get burn rates up to where it will work as a propellant powder. The formula also includes a few parts of dicyanamide as a pre-combustion corrosion prevention. But during powder combustion the temperature is high enough to decompose it so there is no post-combustion corrosion prevention.
When Hodgdon developed the Triple Seven they replaced the sodium benzoate with sodium dinitrobenzoate sulfonate. Highly reactive with charcoal. So in 777 you find a lot more charcoal than is found in Pyrodex and with the rapid reaction rate with the dintro there is no need for the perchlorate.
The presence of sulfur and charcoal in Pyrodex was more of a window dressing thing to get it viewed as a modification of black powder. Without the perchlorate in the 777 it will not cause pit corrosion in the gun.
