BLACK POWDER FOULING & CLEANING

“Black powder? Yuck! That icky, smelly stuff? You’ll be cleaning for hours.”

Oh how many times we’ve heard that! Likewise, how many times have we gotten the desperate phone call or e-mail.

“How do I clean this gunk out of my barrel? I ve tried solvents, XY wonder cleaner, nothing seems to work…..”

Usually there is a stunned silence at the other end of the phone when I offer up the secret magic formula that will melt away that black icky fouling and leave your bore shiny clean.

“Have you tried hot water? Simple H₂O. Its free.”

The Chemistry Behind Black Powder Fouling:

Black powder fouling is the product of the combustion of black powder. (A mechanical mixture of charcoal, potassium nitrate and sulfur) Remember, we are talking REAL black powder not the various generic substitutes. We don’t care about those. What we do care about is exactly what black powder fouling contains. Back powder fouling consists of potassium carbonate (potash) and potassium sulfate. Depending upon the powder brand, there will usually be a 3:1 to 4:1 ratio of potassium carbonate to potassium sulfate. Why is this important? Potassium carbonate remains dry and free of moisture until the relative humidity exceeds 30%. At that point it becomes hygroscopic. (Readily absorbs moisture). In fact, above 80% relative humidity it’s deliquescent. This readiness to become moist (i.e. soft) is the key to easy cleaning. We will get back to this later on.

“I won’t shoot that stuff. It will make my gun rust.” Talk to fellow shooters about black powder and sure enough someone will state the above. Again, we are talking about REAL black powder not the generic substitutes. Black powder does not cause corrosion. Moisture and potassium chloride (if present) do. As for the potassium carbonate, as mentioned previously, when the relative humidity is at or below 30% it will not attract or hold moisture from the air. If no moisture is present then it cannot attack the metal. However, there is a very, very narrow threshold where it just gets damp. It is at this finite point where it can form little spots on the metal that become galvanic corrosion cells. As humidity level rises it rapidly becomes too wet to form individual corrosion cells on the surface and is therefore harmless.

Now lets take a closer look at potassium chloride. This is the bad stuff. To understand it fully we must look at the ingredients that are used to create black powder; charcoal, sulfur and potassium nitrate. The ingredient we are concerned with is potassium nitrate. It provides the oxygen for combustion.

Back when black powder was the only powder available, natural potassium nitrate was imported from India in large quantities. Usually, the various powder mills refined it to remove any impurities. Today, potassium nitrate is derived from potassium chloride reacted with nitric acid. Unfortunately, if the resulting potassium nitrate is note purified sufficiently, then in addition to potassium carbonate and potassium sulfate in the fouling, traces of potassium chloride, which is highly corrosive, will be present. With high-quality powders such as Schuetzen and Swiss black sporting powder, who are painstaking in regards to the purity (99.9%) there will be little concern. With lower quality powders you will be taking your chances.

Many times we have read advertisements stating that this black powder or that black powder produces “moist” fouling. Again, moist is the key to easy cleaning and better shooting. That’s why touting the moisture producing qualities of a particular powder makes good sense. It is indeed true that black powder can be formulated to produce moisture as a product of combustion. However, with the exception of Swiss black sporting powder, none do. In other words the fouling is void of moisture until the bullet or shot leaves the barrel at which point the fouling absorbs moisture from that contained in the in-rushing air. Yes, increasing the amount of potassium nitrate and thus the amount of potassium carbonate in the fouling can alter how rapidly moisture is absorbed but only to a very limited degree. The real key to producing a moist burning powder is the charcoal and the care taken to produce it.

So what makes a good charcoal? It begins with the selection of the wood. The species of the tree is very important. Buckthorn Alder, Black Alder and White Willow were considered necessary for a sporting powder. Rifle and musket grade powders could be produced with Alder or Willow. Hardwoods such as Maple could be used but were considered inferior. Incidentally, Swiss black sporting powder uses Buckthorn Alder, which is considered the best. There are other factors as well. The moisture content of the wood, how long it has aged even the size of the sticks must be factored in. Consistency is everything. How the charcoal is produced is very, very important as well. If the manufacture is using charcoal that could very well have come from the same batch of char that’s currently cooking your steak then I wouldn’t expect much. (The Swiss make their own)

Charcoal is composed of partially carbonized cellulose, minerals and varying quantities of phenolic-structured liquid hydrocarbons and of course pure carbon. The one we are interested in is the phenolic-structured liquid hydrocarbons. More specifically creosote. This is the same stuff that catches your chimney on fire every now and again (for those of you who heat with wood). It’s the creosote that governs how moist a powder will burn. The amount of creosote contained in the charcoal can be greatly affected by how it is charred. For instance, if the temperature of the retort is kept between 300 to 320 degrees all of the creosote will remain in the char. As the temperature rises above 320 degrees the creosote begins to flash off. At 350 degrees all the creosote will be gone. Charcoal with no creosote (solid carbon) will not produce moisture when burned. Simple as that.

Now lets get down to the cleaning part.

Please use common sense:

BE CERTAIN THAT THE FIREARM IS NOT LOADED!!

DO NOT SCALD YOURSELF! WEAR PROTECTIVE GLOVES AND CLOTHING!

When cleaning a shotgun, simply dismount the barrel(s) take a bore mop or patch (100% cotton) soaked with hot, hot water (the hotter the better). Run the mop through the bore from breech to muzzle several times. Make sure to do this outdoors or over a bucket! Now watch in amazement as the hard black goop you struggled to get out with all those fancy solvents simply melts out of the bore.

[Tip: plugging the muzzles will allow you to fill the barrels part way with the hot water. Then you can use a scrubbing motion and it allows the metal to heat-up more efficiently]

NOTE: If you are shooting black powder shotshells using plastic wads, you will have stringy plastic residue to contend with in addition to the fouling. If that is the case then you are on your own. The best advice we can give is that you should have used traditional fiber or paper wads.

Now rinse the bore by pouring hot water through it followed by a couple of dry 100% cotton patches. By this time the barrel(s) should be real nice and hot. Not just warm but hot! Set them aside while you wipe down the stock and lock. When you have finished, the barrels should be cool and any remaining water will have evaporated thanks to the heat absorbed from the water and then radiated by the metal. Now wipe the bore and exterior with your favorite protective oil, re-assemble the gun and put it back in the safe. DONE!

NOTE: Do not submerge the barrels of a double shotgun in water. Moisture is apt to seep through any pinholes or voids in the rib solder and cause corrosion when combined with any remaining solder flux.

If you are far from home and find myself wanting to clean your guns at the range, simply carry along a small plastic pail of water (ambient temperature). I like the small plaster pails. As soon as you are done shooting, and while the barrels are still quite hot, simply perform the procedure described above. The hot barrels will soon evaporate any remaining moisture and your ready to apply your favorite oil.oday we modern shooters have had to rediscover the "secrets' that the shooters of old took for granted. In the course of leaning what was once common knowlege we have fallen prey to many myths. For instance we have a phobia against using water to clean our firearms. However, back in the heyday of black powder, water was the prefered and accepted method. Not only to deal with the various properties of black powder fouling but also the highly corrosive mercury based primers of the day.With the advent of nitro powders this lesson was soon lost and many a firearm suffered heavily pitted barrels due to those same corrosive primers. This could have easily been avoided if they had cleaned thier firearms as of old with good old hot water.