I came across this from Ballistol's FAQ:

Attached File


Just curious if any Ballistol users have ever noticed any issues with their chrome lined barrels or carriers?

In my limited research, the issue with Ballistol and chrome plating is that there may be a copper layer underneath the plating that the chrome bonds to and the ballistol can dissolve it if it creeps underneath the plating. I'm not familiar with how barrels and carriers are chromed, so it may not even be an issue. Maybe someone who knows more about metallurgy can chime in, I'm curious myself whether its potentially damaging to continue using ballistol on chrome lined parts.

Ballistol FAQ

If it doesn't attack the copper it should be fine. Their description is more about their oils ability to get into very small places. Anything used for copper fouling would be a concern certainly.

Chrome plated is different than chrome lined.

Chrome plated usually has the copper alloy base that solvents can erode.

Chrome lined barrels/carriers are not made this way and are not vulnerable to copper solvents.

Good to know that for certain. I figured the processes were likely different, but I couldn't find any info on how barrels/carriers are lined.

Been using liberal amounts of Balistol for years. Never any issues with it on any materials.

I mean I don't mean to sound rude here but use some common sense. AR15s are the most common rifles in America and chrome lining is something that is very common too in millions of different rifles and pistols across the globe. Assuming Ballistol is used for the last 100 years, we must assume that wide spread complaints about chrome lined bores getting damaged by the product would cause a lot more articles and warnings put out there by various companies and Ballistol as a whole, probably wouldn't have lasted as long as they did.

What you find on your bumper is known as "decorative chrome plating," what is in a barrel is "technical" or "hard chrome plating".

The difference between the two.

There is also "thin dense chrome" plating.

Hard chrome vs thin dense chrome plating

Didn't see in the link above, but having done some chrome plating in the past...

Decorative chrome (possibly how they do pistol slides/frames, and certainly how motorcycle chrome etc is done) plates copper first.  Copper is really easy to buff/polish.  Then you plate nickel with chrome on top after you get the copper super shiny.  Caswells, where I got my plating supplies, refers to the chrome as being similar to clear coat on car pain, mainly to protect the nickel.

Anything that dissolves copper, if it gets under the chrome/nickel, will dissolve the underlying copper which is what is plated to the actual object and cause it all to come off.

Barrels are "just" chrome, no copper underneath it, so copper dissolving solvents shouldn't be an issue.