You should definitely try that and see how it goes.
I find it best to NOT give out advice you don't understand.
FWIW grease doesn't work because it is basically impossible to totally fill the bore with thick grease without leaving air bubbles and pockets that will compress under pressure. It has to be oil.
The description of this method as "messy" is a wild understatement. When the metal rod is whacked, oil will spurt out of the muzzle at high velocity. The thing about the mechanics of this method is your head and face will naturally be right above the muzzle when you hit the rod. Give that idea a minute to sink in .............
Oh and let's not forget, that jamming a close fitting steel rod into the rifling and then whacking it with a hammer is probably not going to do the rifling any good.