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Gun Cleaning Clinic: Salvaging A Rusty Smokepole

By: Steve Schmidt

Funny how new cleaning projects mysteriously end up on your desk when you're out of the office for deer hunting – especially the really nasty jobs! After returning from the north woods recently, I found a cleaning challenge unparalleled by any I've tackled before – a Knight, .50 caliber, inline muzzleloader with a badly corroded bore. Let me begin by stating…if you've fired, but not yet cleaned your smokepole this season, do it now before it's too late!


More muzzleloading rifles are ruined each year by neglect than any other type of firearm. This is due mainly to the corrosive nature of black powder fouling and the rapid effects it has on barrel steel.

Black power fouling and that produced by substitutes like Pyrodex® are loaded with potassium salts. The bad news is these salts are extremely hygroscopic, meaning they suck moisture from the air like a sponge absorbs water. This leads to increased dampness in the barrel. Add high humidity to the equation and you have the perfect conditions to grow rust. To make things worse, muzzleloader fouling is highly acidic and will actually etch the barrel steel if the bore is left unattended. What all this means is that serious bore damage and loss of accuracy are the outcome of neglecting your smokepole. It doesn't matter whether your barrel is steel or chrome-lined stainless steel, you need to clean it after shooting…preferably the same day.

All too often, muzzleloaders are put away after the deer season with a dirty bore, forgotten about, and left to deteriorate to the point of becoming unsafe to fire. So, this month's Cleaning Clinic is dedicated to salvaging a rusty, muzzleloader bore. If you need further information about basic care and maintenance of your muzzleloader, I urge you to contact the manufacturer of your rifle or check out the huge selection of excellent, "how-to" articles on the Internet. But, keep in mind that no discussion about black powder rifles gets more personal than cleaning them. Find a handful of methods that seem sensible – try them, then pick the one that works best for you and stick with it.

Since the muzzle end of this rifle looked pretty ugly, I didn't make any promises the rest of the bore could be salvaged, especially since much of it remained hidden under a thick layer of burnt powder. To get a better diagnosis, I removed the barrel from the stock, then the breech plug, and ran a Brownells .50 Caliber Double-Tuff™ Bore Brush (#084-144-500) down the tube to get out the loose stuff. After another look with a bore light, I could tell I was in for a treat. Black powder fouling is always worse in the breech area, just ahead of where the projectile is seated, so it was no surprise to find far more rust at the opposite end of the bore. Even though most of today's high quality, black powder barrels are tempered steel, I was still reluctant to run anything too course down the tube and significantly abrade the lands and grooves in the process.

Plan "A" was to allow the inside of the barrel to soak a spell, hopefully loosening the crusted rust deposits and making it easier to lift out the corrosion with a bronze brush or stainless steel one, if necessary. Since I'd always had good luck with Kroil (#471-100-008) as a penetrating oil on rusty nuts and bolts, I decided to start with it. I didn't have anything handy to fit tight inside the breech port, so I fabricated a rubber stopper to fit inside the flash hole, then reinstalled the breech plug to seal up the back of the barrel for soaking. As a precaution against leakage, I placed the breech end of the barrel into a plastic bucket, then filled the bore up completely with Kroil. I hoped for the best, because I had no plan "B."


The rust formation shown here at the muzzle is representative of what I saw through most of the bore. Because black powder fouling is always heaviest just ahead of where the sabot is seated, the corrosion was much worse in the breech area.

After about 24 hours of soaking, I emptied the bore and wiped the inside of the muzzle with a cotton swab to see if the corrosion had softened up any. It had a little, but I definitely needed something stronger. This rust had bunkered in good, taking up permanent residence like a bad fungus. If the muzzle was this bad, I knew the breech would also be pitted, but I ran both a bronze and stainless steel brush down the bore anyway to see how much rust would break loose. Unfortunately, the results were discouraging.

I knew that Tim Dillon, Brownells Government Sale Manager, had been involved with black powder shooting for quite some time, so I stopped by his office for some advice, and I'm glad I did. Tim didn't hesitate to offer a solution. He recommended the new Brownells Stainless Steel Sponge (#080-000-321) wrapped around a bore brush. "I don't mess around with muzzleloader fouling or corrosion of that kind in any barrel," he said. And, added that chemical solvents often make a bigger mess out of a situation like this. I'll admit, I didn't know what to think. Running stainless steel shavings down the bore seemed a bit drastic in my opinion, but if you know Tim, you know he could convince an alligator it needed more teeth! Tim's vast experience with firearms had never let me down, so I wasn't about to pass on his new cleaning technique.

With plan "B" established, I popped open a pack of our Stainless Steel Sponges and unraveled a piece about four inches long by one half inches wide. As I had implied earlier, this stuff looks a lot like the drill shavings you sweep up off the shop floor, but it's not. It's high quality, flattened, stainless steel wire in a tight coil configuration for serious scrubbing. At first glance, you'd also expect this stuff to really tear up the insides of a barrel, but it doesn't. In fact, I scrubbed like the dickens on the outside of an old shotgun barrel just to see how aggressive it was, and it didn't touch the polished, blue finish. It is tough, however, and I'd recommend cutting it with a tin shears for applications where you need only a small portion.

Starting from the threaded end, I wrapped the short length of wire around the bronze, .50 caliber, Double-Tuff brush, tapering it at the looped end to help make it easier to start the brush into the bore. I then removed the breech plug again in preparation for scrubbing with a cleaning rod. I made my first few passes through the bore and watched as a small mountain of plastic, sabot residue formed in the wastebasket below, that and a whole lot of burnt powder and flakes of carbon. I wish I had counted the exact number of passes through the bore, but I didn't, so my best guess is that I made only a half dozen, back-and-forth strokes before all the plastic was gone.

Since the bore was wet with Kroil before starting the scrubbing process, it was now coated with a thin, brown film of rust, making it impossible to determine how well the sponge was actually cutting the corrosion off the metal surface. I attached a Brownells .50 Caliber Cotton Bore Mop (#084-424-050) to the cleaning rod, dowsed it with Brownells TCE Cleaner Degreaser (#083-060-024) and proceeded to flush out all the excess penetrating oil and loose rust.


Brownells stainless steel sponge wrapped around a tight-fitting bore brush makes a superior rust-cutting combo. It also blasts through plastic wad and sabot buildup and heavy leading in pistol and revolver barrels.

I peered through the bore once again and was amazed at the progress. There was some obvious surface rust still remaining in the breech area and a slight trace near the muzzle yet, but for the most part the bore looked fantastic (considering its original condition). I knew at this point the barrel was definitely salvageable. I re-attached the brush/sponge combo and went back to work concentrating on the stubborn areas. Before long, another half dozen or so back-and-forth passes, and all surface rust was gone.

It was inevitable there would be some pitting in the breech area and slight damage to the rifling near the muzzle, but overall the bore was in fair condition and perfectly "shootable." I gave it a couple last passes with the bronze brush, then flushed it out one more time with TCE before drying it completely with clean, dry patches. A final patch treated with Brownells Rust Preventative No. 2 (#083-019-016) finished it up.

I was so impressed with the Stainless Steel Sponge, that I shared my results with a couple of our gun techs the next day. They weren't surprised how well it worked, and recommended using the same technique on heavily leaded revolver barrels. This should be a huge timesaver for the Cowboy Action Shooter who puts hundreds of cast lead bullets down the bore during practice and competition. Shotgunners should have good luck using it, also, to remove wad fouling.


Revolutionary, new "Tim's Technique" combines your standard bore brush with Brownells new, stainless steel sponge for superior rust-cutting capability. Shown here is a view of the muzzle end after cleaning the bore with this method.

As I had mentioned at the beginning, this month's column was not intended to cover much more than salvaging the rusty barrel. However, the rifle's breech plug and bolt assembly were prime candidates for Brownells EZ-SOAK™ (#083-000-008) , and I couldn't resist including them here.

The chamber side of the breech plug looked completely plugged with burnt powder that had loosened up during the Kroil bath. Matter of fact, I had to straighten a paper clip and poke it through the flash hole a half dozen times to break through the blockage. In addition, some areas on the outer edge of the plug face were caked with carbon. And, as a reminder that ferrous stainless steel does rust, there was the start of corrosion on the milled taper around the flashhole recess.

Here's the same breech plug after soaking in EZ-SOAK. Make sure and run a pipe cleaner through the flash hole to get out as much carbon buildup as possible. If the plug is damaged in any way, REPLACE IT!
Shown here is the chamber end of the breech plug riddled with carbon and slightly corroded. A plugged flash hole can lead to unpredictable hangfires and misfires, so the plug must be cleaned.

The nipple end of the plug had some carbon buildup as well, on and around the hex collar and inside the flash channel. Plus, the threads were gunked-up with old, anti-seize compound.


The stainless steel breech plug cleaned up nicely. Luckily it was only dirty, and not seriously corroded. Rust can weaken the threads, causing a very dangerous condition for the shooter.

The stainless steel bolt also had some problems – slight rust formation forward of the firing pin hole and some thick, carbon buildup. I unscrewed the firing pin/cocking piece from the bolt and checked it out. It didn't look just too dirty, so I hit it with TCE and a parts brush, dried it good and sprayed it down with Rust Preventive No. 2.


A view of the breech area after final cleaning shows the corrosive effects of black powder fouling on barrel steel. The stainless steel sponge worked great to remove the surface rust, but the pitting cannot be reversed.

I then dropped both the breech plug and bolt into a jar of EZ-SOAK for 20 minutes, and followed up with a nylon-bristled parts brush. It didn't take a minute of scrubbing, and they looked like new again. If you read last month's Cleaning Clinic, you'll recall that EZ-SOAK was first developed to tackle shotgun parts, particularly carboned-up gas cylinders and chokes tubes. Well, I can testify it works equally well on inline muzzleloader parts. This wonder cleaner saved me a heck of a lot of elbow grease and wasted solvent. What also impressed me was that the EZ-SOAK actually cut the light surface rust on both parts.


Before and after photos of the bolt face show the cleaning power of Brownells EZ-SOAK. It's not just for shotguns and revolvers anymore!

You probably think saving the barrel on this old friend was a lot of work, and you're right. But, remember, cleaning your rifle after every outing will help you avoid this predicament. Brownells carries a full line of cleaning products to help keep your smokepole in good, serviceable condition so it functions reliably in the deer woods every season.

If you have questions about different cleaning products or techniques you want us to test, be sure to let me know at WebBench@Brownells.com.