Optically center your scope then add a shim under the rear ring so it points the scope downward. shim can be made from a playing card or a piece of aluminum can. Don't over tighten ring caps. could also be your scope mount or stop pin alignment.
I like the Crossman 1377-22 because of the variable power, you can decide how much power you need. I lived in an old (raised) wood framed house and field mice would come in on occasion for a safari.
tho those 34s shoot pretty good even with a little wind.my original M1 Impact 600mm ST .25 shot them @ 910fps out to 100 MOA and beyond. Good luck with slugs, post pics(y)
There lays the problem, you get sub to MOA groups but think "I know I can do better" lol. Lots to factor in day to day and even hour to hour when shooting groups.
Where I live used to be rural, lots of wildlife including fox, squirrel, racoon etc. Now with all the building of subdivisions you rarely see any of them. The way I see it is everything has to live somewhere and be thankful they are not all gone.
that lower stock section in front of the trigger pops out and forward open annd close to pump. the more pumps mthe harded it gets drops down and swings forward and back