Mossberg 930 gas cylinder fouling

[AngryWaffle]

Took my 930 JM Pro out for a second time, I put about 215 rounds through it. I've only ever shot about 500 rounds through it. When I go to wipe out the gas cylinder I noticed there was alot of fouling, I think it's lead?? Whatever it is I got most of it off (and there was alot), but the rest won't budge.

I took a picture of what is left in the cylinder, suggestions?

Edit: ChoreBoy Copper Scrub does the trick. I shot about 40 slugs that day too. Probably the worst mess I've ever had to clean.

 

[jeffy56]

Investigate different brands that might have a better shot/slug cup that lets the load get past the gas port with less fouling. Also, some loads like S&B buck are longer. This might affect mag load or 1st round cycling.