Now that is one I have never heard of! Makes more sense than a drill.I had one like that, I thought about epoxying a cleaning brush to a sawzall to run in and out of the barrel. It took a solid week to find the pitting under the carbon and copper. It did shoot great but had a rough throat!
I think a little JB bore paste in the blue can and a brush would be less aggressive than that the sawzall. I have only done that once but it brought a gun back from the grave in a short amount of passes.