That's the beautiful thing about the Ruger 10/22, they don't often need parts. I've had one since 1989 and the thing is like the Energizer Bunny. Add my HotLips banana clip, and it carries 50 rounds. They even make speed loaders for the banana clips, try that with the Marlin and the barrel tube.
My Marlin is 37 years old and is still working perfectly.