Cleaning of chrome-lined barrels

[P30]

1) Is it good practice to clean chrome-lined barrels with ammonia-based cleaners from time to time in order to remove copper residues?

Sometimes I've read: The ammonia gets through little cracks underneath the chrome-lining. There is supposedly copper. The ammonia removes the copper under the chrome. And then the chrome-lining flakes of over time. I doubt that's true. But I'm not sure.

2) What kind of cleaner do you use to remove copper residue from the barrel? It's not necessary to name a specific brand, the kind is sufficient (e.g. "ammonia-based"). In order to enable others to judge how good your cleaner works, it would be very nice if you add the following data:
a) Since how many years or shots do you use the cleaner?
b) What's the precision of your rifle (in MOA)?

3) After how many rounds do you clean the barrel with a copper remover?

4) Which cleaner is used in the US military for barrel cleaning? What kind of brush is used?
Cleaner is Break Free CLP, I assume.

[Duelist]

I don’t recall using anything but CLP for weapons maintenance in the military. I wasn’t in any type of special tactical unit, but we did keep our weapons clean and lubed.

Copper bore and chamber brushes.

Nobody I knew kept a round count but me. My rifle had less than 1000 rounds through it from new until I turned it in for the last time, about 6 years of use.

[blues]

I know G96 was approved for military use...

http://www.g96.com/products/military...c-clp-gun-oil/

http://www.g96.com/products/military/

[LittleLebowski]

I wouldn’t overdo this. Clean every 1000 rounds or more, also clean if accuracy drops off.

[Unobtanium]

I've always just used a boresnake for 3 passes or so because bores get dirty with suppressed use, as I use them. Thousands and thousands of rounds, this is how I do. The guns always hold around 1-1.2moa with ammo they like.

Hoppes 9 or clp or whatever seems to work. Never harsh chemicals or foams.

[Dan_S]

I wouldn’t overdo this. Clean every 1000 rounds or more, also clean if accuracy drops off.

And when you do clean, use a good (non metallic) rod, sweep breech to bore, etc etc.

[farscott]

Best practice is to avoid ammonia-based cleaners with chromed barrels unless you are sure that there is not a copper base coat. If there is a copper base coating, which was the case with the old-fashioned nickel electroplated finish, the ammonia will attack the copper base coat as the chrome coating can be penetrated, especially at cracks and edges. Once the copper base coat is compromised, the chrome lining can stop adhering to the barrel. That being said, you can use ammonia-based cleaners with chromed barrels IF the bore cleaner is not left in the bore for longer than, say, fifteen minutes. If this was not the case, a bronze brush would fall apart in the presence of a copper solvent. If you do use ammonia-based cleaners, it makes sense to remove as much as possible and follow up with a CLP or oil.

I personally just use CLP, chamber brushes, bore snakes, and oily rags as I rather not deal with ammonia. I have been cleaning this way since the 1990s, and I tend to clean any rifle after it is used, no matter the round count, as it is very humid here. Some residue is hygroscopic and can cause corrosion, so I just make a practice to clean after shooting.

[txdpd]

FWIW the Barnes people will tell you that CR10 is safe on chrome lining.

If you need to remove copper your two readily available options are abrasives or ammonia. I've never needed to clean copper residue, (not to say that I haven't) from a chrome lined barrel but if I did I would go for ammonia.

Also the chrome plating in a barrel isn't like the plating on a truck bumper, it's an microscopically thin layer of chrome. If you burn or wear through it, it'll show up as a little grey residue on a cleaning patch. Think of it like car wax, it wears away slowly and you won't know it's gone until you have something going on where it should be.

Edited: To answer the original question, I don't think it's a good practice to use copper cleaner in chrome lined barrels, unless there's an identifiable problem.

[Colt191145lover]

I rarely clean my chrome lines barrels but do the same thing as a standard barrel. M pro7 cleaner to remove the carbon fouling. I don't remove copper unless accuracy drops off.

[farscott]

A few additional comments.

1) Most modern hard chrome processes do not use a copper base coat. The chromium is directly electroplated onto the base material. The finished chrome thickness can vary with geometry due to the corona effect and how the work piece is suspended in the plating tank.

2) Corrosion stress cracking of steels in the presence of ammonia is a real thing. Hard chrome has cracks which allow any ammonia in the barrel access to the barrel steel. I do not believe this to be a real issue unless ammonia-based cleaners are extensively and repeatedly used, but I am cautious about ammonia and stainless steel barrels. While many stainless alloys are resistant to ammonia corrosion stress cracking, my experience with stainless barrels is that the material is more likely to rupture than a carbon steel barrel when it does fail. So combining stress corrosion and a material that when it fails is more likely to rupture than carbon steel barrel alloys makes me cautious about using ammonia-based cleaners. It may be much ado about nothing, but I exercise more caution with ammonia and stainless steel barrels.

3) I have not needed to use ammonia-based cleaners on a chromed barrel. My experience is that Kroil will get under the copper fouling and allow it to removed through mechanical means if needed. I have only done this with one rifle, which had a very rough bore.