Tried both in my .457 Texan (which is only single shot) and did not have very good luck with the .357/45 sabots which I attribute to the rifles twist. 5" groups at 50 yards on a rifle that can do 1.5" at 100. Tried everything from 125 to 160 gr bullets, jacketed and cast.
I used to shoot 45-90 BPCR paper patch (and .458 Winchester Mag paper patch) at 1000 yards so I have several molds for that but they are all too heavy for air rifles as they are all 450gr and above. Since I had gotten better than jacketed accuracy back then, I did try it with a .454, 290gr heavy weight pistol bullet sized down to .452 and PP using Rooster Lube on the paper (which is not just regular paper but is best when it is long fiber 'rag' paper which is almost impossible to find today. When it started getting scarce I bought a lifetime supply, sorry, haha). Note I have found Rooster works fine all by itself on cast bullets in the Texan to keep the bore clean and has not been detrimental to accuracy like some lubes are. It also has the advantage that it is a dry lube and does not pick up dirt like the soft wax or wet lubes do in the field hunting.
I did get just as good of accuracy with PP as plain lead slugs if not a tiny bit better and the bore actually stays both clean and begins to appear more polished after several hundred rounds testing. I believe it has promise but perhaps needs a more custom weight and design shape more suited for PP than what I used to test with.
I would also recommend people interested in PP go to the CastBoolits forum (spelled right) as it is a treasure trove of information on this subject and there are some master shooters of PP there.