I went out and bought the GM oil as recommended, the device sat soaked in oil for over 14 hours, but no joy! I am at my wits end

I made the barrel vise block, tightened the vise to the point where I can't turn the lever anymore, but the barrel still rotates when I use the wrench on it! On top of it, the barrel front is slightly marred now from the friction tape (I thought that stuff didn't mar...guess not!). The can will cover the slight marking when installed, if I ever can get the darn thing off!