I've been reading this thread with some interest. I purchased a Ruger .22PPC while they were being made and although it shot rather well, I ended up being very disappointed with it. You probably all know what a pita it is to form cases.. I went through that in spades. Would definitely recommend against it (use the 22 PPC USA cases if any are available) particularly if you'd rather shoot than reload, spend time fireforming, and generally tearing your hair out.
Next, considering case capacity and all that, remember that this round won't really do anything that a good .223 or .222 Magnum won't do. The round's biggest failing (OK, ignore this if you're a pure benchrester, are used to such things, or are just determined to press on anyway...) is the short, fat case and 30 degree shoulder. With these, as the case stretches and gets tight in the chamber, it's really impossible to move the shoulder back to achieve a small headspace clearance for good function.. Yes, I know folks use "bump" dies and all that and "think" they're doing this, but for the most part all they're doing is collapsing the case walls, which spring right back as soon as the round's fired. The smaller diameter .223 series rounds do allow for actually setting the shoulder back, but with the PPC's this is mostly an illusion imho.
This leads to my third point, the rifle itself. The Ruger folks used a stainless receiver and a stainless bolt. Apparently neither is particular hard or gall- resistant. When my rifle "locked up" a few times due to the case problem above, the lugs and lug seat galled horribly... even though lightly lubed as I recall. Someday I really do need to take the barrel off, refinish the lugs and seat, take it up one thread and rechamber.
I'd gladly sell the gun, but I wouldn't want to put it into someone's hands with about .006" excess headspace and galled lugs. It works "sort of" ok if I keep a coat of never-seez on things. Accuracy wasn't bad, maybe on the order of .5" or slightly better, but then a lot of rifles will do this. Nothing to write home about.
I look on this whole thing as a "learning experience", but one that I'd rather not have again. And I realize that many won't share these opinions, are much more forgiving of the PPC cartridges than I am, and so forth. But if I were looking to do anything besides just play with the particular rifle and cartridge, I'd look for a .223, etc. on something other than the Ruger action....