A rifled slug or Foster slug can be shot thru a fully rifled barrel, with pretty good accuracy I'm sure. Well maybe for the 1st two or so shots, then severe leading of the barrel, lands & grooves will be experienced.
For a rifled barrel, there are saboted rounds available, Win., Federal & Remington to name a few. I fired some Brenneke slugs designed for smoothbores as well as 2x Win. 1oz slugs and 2 Federal 1oz slugs which leaded my screw in rifled choke tube, This was done with barrel swabs in between too.