The Dirty Little Secret of Gun Cleaning
A gunsmith who’s cleaned thousands of gun barrels reveals what so many shooters do wrong—and make their rifles shoot badly.
I’m the gun guy in the neighborhood, and my gunsmith shop is the first stop when somebody is having gun troubles—often an accurate rifle that suddenly started misbehaving and spraying the target with patterns instead of tight groups.
I have a checklist of steps to correct that, but my first step is to ask the gun owner a question:
“Did you clean the rifle?” I’ll ask.
Many will insist to the point of confrontation that they “already cleaned it.”
So, I’ll take the rifle, and my first step is to clean the “already-cleaned” bore, and test-shoot the rifle. I can’t begin to tell you how often my cleaning alone will fix the problem.
When that shooter comes to pick up his gun, I smile, hand them back a rifle that is shooting well again, and let them think I am a miracle worker.
The truth is that while many people think their gun is clean, it really isn’t.
Clean to Bare Steel
Many shooters run a few patches through the bore, maybe make a pass or two with a brush, and assume that they have cleaned the rifle. That’s the equivalent of running your car through a puddle and claiming you washed it. Even scrubbing the bore for days doesn’t ensure the rifle is clean, because if you’re using the wrong solvent, it accomplishes nothing. Sometimes guns are so badly fouled it takes longer than that, even with the correct solvent.
I once spent a week cleaning a badly fouled .17 Remington rifle. I didn’t know it was physically possible for that much copper to be trapped in so small a bore. Another time I had a .338 Winchester that was fouled so badly that it looked like a smoothbore.
One man I know bedded his rifle barrel because it was shooting badly. The bedding didn’t fix his accuracy problem. He gave the rifle to me to check, and the bore had so much copper in it I almost could have sold it for scrap. He didn’t need to have bedded the rifle after all.
The key is to clean the bore down to bare steel, and remove all powder and metal fouling. If you can accomplish that with a few patches, fine—but it doesn’t happen often. I have a few high-end barrels on custom rifles that foul so little, they clean up with just a few patches. But those are very rare critters, and most rifle barrels will require some effort to clean.
I can’t say how many patches or how many swipes of the brush will be required to clean any specific rifle, nobody can. What I can do is explain how you’ll know when you’re done.
The Proper Cleaning Technique
This process involves strong solvents, so glove up, use eye protection, and make sure there’s plenty of ventilation.
Clean from the rear of the rifle when possible, and always use a cleaning-rod guide to keep the rod centered in the bore, and to prevent crud from getting into the action.
1. First Solvent
Wet a patch with a solvent that will remove both powder fouling and copper fouling, such as Hoppe’s #9 Benchrest, and run it through the bore. Do this several times. It’s best to use each patch for only one pass before replacing it with a new solvent soaked patch, but I do sometimes use both sides of the patch at this stage of cleaning. You may want to let the gun soak a few minutes between patches to allow the solvent to work.
If you want to shoot straight, you’d better watch what you stick down your barrel. Here’s how to choose a good cleaning rod.
2. Bronze Brush
Having left the barrel wet with solvent, use a properly fitted bronze brush soaked with solvent to make several passes. It’s important to keep the brush wet, so reapply solvent after every couple of passes. Don’t dip the brush in the solvent bottle, as this will contaminate the remaining solvent. Instead put some solvent in small container and dip the brush into that. I keep a supply of small Dixie Cups in my shop for this use.
Never reverse the brush while it’s in the bore. Instead, push it all the way out of the muzzle then pull it back through the bore. After using the brush, always remove dirty solvent from it with a degreasing spray. Let it run off the brush and so you flush away the gunk. This is to prevent abrasive debris from accumulating. Also, some solvents will eat the bronze bristles.
3. Let the Solvent Work
Let the gun sit for a few minutes to allow the solvent to work, and then follow with a couple more wet patches. Wait a few more minutes and run a dry patch through.
4. Dry Patches
Now remove all traces of the first solvent by running dry patches through the bore. Then run some patches soaked with degreaser, such as Outers Crud Cutter, followed by a final dry patch.
5. Strip that Copper
Wet a patch with an aggressive copper removing solvent, such as Sweet’s 7.62 or Barnes CR10.
Run it through the bore and let it sit for a few minutes. Then follow with another wet patch, wait, and repeat. The goal is to have no blue stains on your patches, indicating that there is no remaining metal fouling. (Remember, though, that a brass jag can leave a “false” stain on the patch, although it’s usually on the inside rather than the outside of the patch, so it’s easy to distinguish stains from bore fouling. When in doubt, use a cleaning jag.) When your patches come out with no trace of blue—and this may take a while if the fouling is extensive—dry the bore with several clean dry patches.
If you want to speed up the process here, use a brush. Many sources recommend nylon brushes, but I don’t think they are aggressive enough. I use a bronze brush with the understanding that these strong solvents will eat the brush. Even if you clean the brush with a degreasing spray immediately after use, it’s only good for a few cleaning sessions.
In fact, after scrubbing with a strong solvent and a bronze brush, there will be a lot of blue gunk on the next patch through the bore. Some of that is from the bore, and some is from the dissolving brush. So, treat brushes as consumables, just like the patches and solvents. Buy a few extra brushes so you have them on hand.
Most aggressive copper solvents recommend that they not be left in the bore for more than 15 minutes, so keep working with patches and brushes to refresh the solvent often.
6. Switch Solvents
It’s possible to have copper fouling trapped between layers of powder or carbon fouling. To be sure that’s not the case, I like to switch solvents at this step and go back to the general-use solvent like Hoppe’s #9 Benchrest. Again, it’s important to remove all traces of the old solvent before introducing a new solvent, so be sure the bore is dry before doing this.
7 Break out the Kroil
If the bore is really fouled, the old benchrest shooter’s trick of using Kroil penetrating oil and J-B Bore Cleaning Compound can help loosen things up. Kroil has excellent penetration qualities, so it will work in under the fouling. J-B compound is mildly abrasive to help remove fouling. However, it will not damage the bore.
Wet a few patches with Kroil, saturate the bore, and let it soak for a while.
Then wet a tight-fitting patch with Kroil and then coat it with J-B compound. Run it through the bore a bunch of times—at least 20 passes, twice that is better. Check the patch often and add more J-B as needed.
8. No More Blue
Clean all the goop out of the bore and follow with a couple of wet patches using an aggressive copper solvent. Let it stand five minutes then run a clean patch. If it comes out with no blue stains, you are done. If there are blue stains indicating there is still copper fouling, keep repeating this process with both the solvent and the Kroil/J-B combination in rotation until there is no sign of blue on any patches after letting the aggressive solvent work for five minutes.
Like I said, sometimes it’s a fast process, and sometimes it seems that you will never get the darned thing clean. But, until you can soak the bore with an aggressive copper removing solvent, wait a timed five minutes, and then run a clean patch through without blue staining, the gun is not clean.
Very often this will correct the accuracy problems. But, even if it doesn’t, a thorough cleaning will eliminate one big possibility off of your checklist, and your rifle will be better for it.