I haven't tried that Rhineland kit, but I'm suddenly interested. Way back in the dark ages I bought a 5 pack of Mausers from Century, and one of them had a huge divot in the chamber. It would make a perfect donor action for that kit. At this point I can't remember if it was a 24 or a 24/47, but both of those are listed. Looks like they're using the lock ring system like centerfire Savages, which is easy enough to work with.
Not that I've ever thought I needed a 45ACP Mauser, but the rifle I've got is useless without a rebarrel anyway and I have other Mausers, and....