Last fall I gifted myself with a new Mossberg 930 as a duck/turkey gun. I like it. Shoots great with whatever I feed it. But, to date I have been unable to get a patch to come out of the barrel clean. I have run into this once before on an old Stevens 311. I was the local gun guy where I worked and a guy came to me and asked if I would clean his gun and I agreed. I used everything but battery acid on that 311 and finally gave it back to him still turning out black patches. Now I seem to be having the same deal with the Mossberg. Any body else ever run into this?