Copper in comp

[Braxton1]

I went to clean the comp in my SuperComp gun last week. There was the expected amount of carbon buildup, but no lead (I only shoot 121 Grain HPs in this gun; no exposed lead on the base).

What caught me really off guard was the amount of copper that was brazed inside the first comp chamber. Anybody ever seen that before?

I checked the obvious (no bullets striking the sides of the exit hole).

I am using 4756 powder at a 169 pf.

[OpnBlstr]

I used to shoot a short open gun that deposited copper in the first port.

It would chip out with a sharpened screwdriver fairly easily as long as I let it build up somewhat thick so I could bite into the edge of the deposit.

Since I went back to longer barrels without blow holes my loads are tamed down enough that my current guns don't do this.

[Radical Precision Designs]

This is a very interesting happening.

Many shooters switch from FMJ's because of the "exposed" lead out back, expecting no "metal" build-up at all ... then find out they are still getting build-up, but copper or brass instead !!!

It is very simple, really. The gasses pushing the bullet are hot enough to vaporize most anything given enough "static" time to work on that surface. The softer (maleable) the metal, the faster it will erode/melt from the hot blast. Ever wondered why aluminum comps don't last ??

Whatever metal is "hotly vaporized" is impaled against the comp surface, not that dissimilar from a soldering action. Fortunately it is a bad "soldering" job that can be undone easily enough by mechanical means. The trick here is to not let it build too much before scraping off. The thicker build-ups can be a real hassle to dislodge, while thin ones scrape off easily.

[jostein jensen]

is it easier to remove if you blast through a mag to heat the comp a little, or does it just burn fingers?

[Jaxshooter]

I pour Kroil in the comp and let it sit overnight. The Kroil gets under the copper and makes it real easy to get out. Just tilt the gun enough to keep theoil pooled in the comp chamber.

[KGentry]

I soak my comp in Hoppes#9 and after a couple of days - nothing but clean metal in that there comp - if you soak for a couple of hours every cleaning it is much easier. I run a True-Bore setup so no worries on the lock-tite.