What actually causes copper Fouling

[jlopez]

I find lots of topics on how to clean copper fouling but can not find a topic on what actual factor cause less or more fouling.

Logically I would think faster speeds would be a cause but at what point will this make a difference?

Also I would suspect the alloy mixture of the copper jacket will vary between manufactures and will effect this.

Will bullet weight vs barrel twist rate make a difference?

Will ball vs a stick powder or different powders?

What other factors can be controlled to lessen copper fouling?

Juan

 

[Graham]

Re: What actually causes copper Fouling

Copper is softer than barrel steel. As to quantity, a .308 won't become a 7mm if you don't clean it. Buy a barrel that has been properly lapped after manufacture, and don't worry about trying to reduce fouling after that.

 

[918v]

Re: What actually causes copper Fouling

I noticed that pure copper bullets lay copper everywhere, even in the corners of the lands and grooves. Copper alloy jacketed bullets lay copper in the middle of the grooves and on top of the lands.

Velocity and pressure cause fouling. I have fired my Remmy 308 for over two hundered rounds without cleaning the copper, just brushing the carbon out. It does not copper foul.

My 22-250 copper fouls a little bit, even though it has a Krieger barrel. But those bullets are going 30% faster.

 

[MitchAlsup]

Re: What actually causes copper Fouling

As a guilded bullet travels down the barrel tiny little flake come off, especialy durring the engraving process. These little slivers of metal are exposed to temperatures well in excess of the vaporization point of copper (and zinc). So the slivers of metal become part of the gas.

As the bulet passes the half way point in the barrel, the temperatures have dropped to the point where the metal quits being a gas and starts being a liquid. When the liquid encounters the cool barrel metal, and then sticks like solder to it as it freezes back into metalic copper.

The reason we find so much copper at the edge of the rifling, is that it is easy to clean from the other parts of the barrel with std patches and brushing techniques.