That’s some impressive ... and expensive ... hardware. Still falls short of a .22LR, though. Good news is it can be suppressed without NFA complications. And those airgun suppressors work quite well.
Those are just a couple rifles, they get much more exotic and expensive.
Then, there's the necessary accessories. A scuba tank with regulator and fill hose will cost approx another $600 then you will need a scope.....
They're not for the faint of heart.