I have a T/C white mtn carbine with a green mtn LRH barrel. I was cleaning after a range session today and shone the light down the barrel after I thought I was done. I noticed a cavity at the bottom in what I presume is the breech plug. It is a smaller diameter than the bore, and I looked and there was still black crud in there. Is there a special tool to get in there and scrub it out? The jag and patch can't get in there.