That’s an expensive varmint gun.
Buy a used Marin 60 for about $40 to kill the rats and crows.
Then spend the other $540 on ammo for your real self-defense weapons, on long-term storage food and other preps for emergencies.
My brother in law handed me an old Marlin 60 to repair in return for his plumbing services. He knows squat about guns except how to pull the trigger.
His son lost the magazine tube capture rod - ordered and replaced.
DIRTY as hell - never been cleaned...a little cumbersome on breakdown to clean thoroughly but once I understood that not too bad at cleaning. I spent quite a few hours on cleaning it up sanding/restaining/coating the stock, etc. but it was a beauty when I gave it back to him.
The next thing I did was to go buy a new one and put a good scope on it....a damned good reliable accurate plinker for around $150..
Watch how on “Swamp People” a nondescript .22 rifle of any make is used to turn ten feet of raging alligator into inert lizard meat. Shot placement critical.
The .22 Sturmgewehr looks neat, but I’ll keep my $300 CETME rifle for now. Strong family resemblance, though.