I used a stainless tornado brush extensively in Cordoba, where my chambers would build up with plastic residue badly due to the high volume and rapidity of shooting, which built up heat in the barrels. The 687 SPII Sporting would get sluggish ejecting, then stop if I didn't stop soon enough. A few quick strokes with the tornado brush in the chambers would totally restore ejection. It did cause me some brief grief at the airport in Santiago. I had inadvertently left it, with a brass handle screwed onto it, in my shell bag which was stowed in my luggage, not in my guncase where it probably should have been. A tense Chilean airline security guy thought it might be a weapon when he saw it on the x-ray screen. He called me back to look at the screen and asked in his most stern Spanish what it was. I, in my best Southern drawl, tried to allay his concerns. With a big frown he motioned me on my way.
I can't see how one could hurt a bore. You're not going to be scrubbing it for hours at the time and there's no sharp ends.
