I decided to do a good scrub on my Blackhawk yesterday. I bought a new 45 caliber bore brush to run though the cylinder chambers, as the 9mm brush barely touches the chamber walls. I usually scrub 2 or 3 passes in each chamber unless there is obvious crud that didn't come out. The brush started shedding bristles like my dog in spring. Am I doing something wrong, or did I just get a bad brush?