Treating Your Barrel

Many people have "heard" that molbdenum disulfide can actually harm barrels by corroding or encouraging corrosion and pitting. Well, in this article, Precision Shooting Magazine dispells concerns about using Molybdenum Disulfide.

The instructions that come with the Ms. Moly spray are very thorough. I suggest that you follow their instructions, with the following modifications (or comments):

1. For barrel conditioning - Make sure the barrel is clean, clean, clean. I clean the bore with powder / copper solvent, then spray it out with carburetor cleaner (laquer thinner). Then I use my Outer's Foul Out II System. I follow this with another bore cleaning, spray it with carburetor cleaner again, run a patch through, and wait a few minutes to make sure it is all evaporated.
2. If you're starting out with a brand new barrel, you should consider polishing it first. First clean the barrel (above), then smear a mild polish (like 'Flitz' or 'Kleenbore') into a patch wrapped around a new bore brush (a slotted tip or jag will also work, but I prefer a new bore brush) that fits snugly in the bore, and run it 20 times back and forth through your barrel to do an initial' smoothing - don't let the patch exit the muzzle. Do a normal cleaning, polish (now go 20-50 times back and forth), clean, polish, etc... until you feel your barrel 'smooth out' - you will definitely know it when your barrel 'smooths out'). Then clean, polish twice more. (Expect that, no matter how clean your bore is, the patch with polish will turn black.) Then do a really thorough cleaning and spray it out with carburetor cleaner (laquer thinner) before proceeding.
   Sources for 'Flitz' polish:
   • Your local gun shop or hardware store
   • Official Flitz WebSite
   • Caswell Inc.
   • Shine Enterprises
3. Condition your bullets or bores either outside, or in a workshop with good ventilation. Ms. Moly gives off quite a strong petroleum odor, and is messy to work with when conditioning bores (bullets, less so). Marksman, Inc. puts a clear WARNING on the spray cans concerning your health.
4. Swap aerosol spray buttons with one that will accept an 'extension tube' (WD-40 and most carburetor cleaners have one of these). This will help you reach into the bore without splattering your action or chamber.
5. Initially, spray the bore in a vertical position from the breach end with the muzzle down and an old rag on the floor to catch the drippings. Use 1 second bursts every 5 seconds until it starts dripping out. (I did not find it necessary to spray from the muzzle end). Then,
6. Put the gun in a cradle, with the muzzle slightly lower than the breech, and an old rag (the one you had on the floor is fine) draped over the muzzle to catch the 'initial spray' from the first couple of passes through the bore.
7. Like the instructions say, don't spare the rod. They suggest a half dozen or so passes of the brush - I made between 30 and 50. It doesn't take much longer to do (this is the easy part), and it really seemed to burnish Ms. Moly into the bore. I did this 3 or 4 times.
8. I used Gumout to clean overspray off my barrel, action, and synthetic stock, and then applied WD-40 or TRI-FLOW to protect the finish.
9. According to Marksman, Inc : moly treatment, done correctly, will provide a 1.2 micron buffer zone that is 3.27 times harder than a steel barrel.
10. Note: It is IMPORTANT that you run a patch of oil down your bore after normal bore cleaning or if you are planning to store your rifle for a while, as MoS₂ does not inhibit corrosion.

It is interesting to note that the instructions that came with Ms. Moly suggest that a pass or two with a dry brush, and then a dry patch may be all that is necessary to clean a bore treated with Ms. Moly. But, old habits die hard ...

My barrel cleaning procedure is basically :

• Insert your bore guide
• Attach a bore brush to your cleaning rod and apply a mix of two parts Shooter's Choice powder solvent to one part Kroil (SC/Kr) to your brush
• Push-pull the brush two or three times through the bore to loosen the powder fouling
• Replace the brush with a brass jag
• Wet a patch with SC/Kr and push it through your bore
• Wet a second patch with SC/Kr and push it through your bore
• Make two more passes with a dry patch
• ... if you're ready to put your firearm away ... make a pass with a patch covered with a light oil, such as Kroil, Outer's, Hoppe's, or Marvel Mystery Oil
• ... otherwise, keep shooting ...

Removing Moly

I noticed when cleaning up after conditioning the bores of a few firearms with 'Ms. Moly Ballistic Conditioner' that some solvents clean better than others. In cases like cleaning up any overspray off your rifle, it is desireable to eradicate all traces of the conditioner.

I got curious as to which solvents that I had 'on hand' would eradicate 'Ms. Moly' overspray. I tried everything that I have in my workshop and recorded the results. They are rather subjective, as I had no way to really quantify them, but I hope the following information is useful to others. The following solvents were used to clean Ms. Moly off a piece of aluminum:

Key:
      excellent - nearly instant removal of all Ms. Moly
      very good - light wiping required
      good      - light rubbing required
      fair      - moderate rubbing required
      poor      - fair amount of rubbing required to remove any Ms. Moly

The following are the results of solvents that I would not ordinarily use for gun cleaning, but my curiosity got the better of me.

Bear in mind that the aluminum block used in this test is NOT made of the same material as a rifle barrel, nor was it 'consolidated' into the metal that was treated. The instructions that come with Ms. Moly tell you to fire 10-15 successive rounds of moly conditioned bullets through your barrel until it is hot to the touch in order to form an 'intermetallic buffer zone' in the bore. Just remember not to get your barrel too hot, as you may ruin the barrel. How hot is "too hot"? If I can't firmly grab the middle of the barrel and hold on for more than ten or so seconds, I would consider it too hot.

It is my understanding that once the rifle is fired, the sulfur in the MoS₂ acts as a halon to actually bond the moly to the steel of your barrel. Anything short of an abrasive will not remove the moly.

FINAL SUGGESTION : Treat your bores with Ms. Moly (or similar) spray, treat your bullets and plastic sabots with NECO or Midway's Moly Powder. I put my bullets and treated BBs in small --> medium sized plastic jars and then lay them in my tumbler.

There are a few solvents that I have not tried (Sweet's, Barnes' CR-10 Copper Solvent, Outer's Crud Cutter or Nitro Solvent, Pro-Shot cleaners, Break Free Gun Cleaner, etc.). If you have tried any of these or other solvents, please send your results to me for posting. Thanks.

Last updated : 01 March 2000