I just bought a Security 9, i decided to clean it before shooting it. i took it apart and there is a grayish brown spot aout halfway around inside the chamber more gray and very light brown. i can't see anything in the barrel and half of the chamber is good. it's not rough feeling and ammo cycles good by hand. taking a plastic nozzle straw from my rem oil i can't feel it catch on it so it has to be very thin or may be in the bluing. My bronze bore brush won't clean it off, it has me stumped. i have oiled it and put everything back together and cycled it. and it cycles fine by hand. I am thinking it's part of the bluing that didn't take well but wanted to ask here. thanks for any help on this.