I'm having a hard time cleaning the barrel of my new Bersa. I have shot 360 rounds used Winchester white box ammo and Hornady American Gunner. I use a brass brush and a nylon brush soaked in either Hoppe's number 9 or Rem Oil. No matter how many times I brush I still see streaking in the rifling. I can brush, squeeg-E and still the patches come out a little dirty. Is there a different product I should use? And is this common for the Bersa? My Glock is a breeze to clean. Thanks for any info.