PP Bullets in a Tube Magazine Rifle?

[Kurt]

The lube would not be much of a problem. I would worry more about the rolled back patchwhen the round gets pushed off the ramp and at an angle into the chamber.
I loaded some dummy rounds for the .444 in my Marlin and ran them through the rifle and most of the patches where damaged.
Don't do this with live rounds. If you stick a bullet and the hammer drops on the next might not be the best for you and your rifle.