I ask a popular Field Target shooter what he does to make his Marauder rifle shoot consistant small groups. He shoots a .177 caliber, but the same should apply to the .22 cal. Here is what he said:
"Clean the barrel then Clean the barrel ,Clean the barrel ,Clean the barrel ,Clean the barrel ,Clean the barrel ,Clean the barrel
and when you think it is spotless then Clean the barrel.
Then lube your pellets. Slick 50 one lube. Try them sloppy wet. Try them just damp and even almost dry. CPL's on mine liked to be pretty wet. JSB and Air arms 8.44 shot best dry and then I pull a bore snake every morning before I start sighting in for a match. At the Nationals I shot a 5 shot clover leaf group on the 50 yard paper shot at a diagonal in the wind. I held the same place and they just all stacked. Not where I aimed but they stacked.
You have to find the right combination of pellet and lube that your gun likes and also chrono it to make sure you are shooting within a tight spread. there will be one pellet that your gun likes above all others. You may not have found it yet.
A few other tricks.
My stock screw is loose. the inletting is relieved so that I can run a paper around the reservior and slide it all the way to the guage port and to the front without it binding. That way any pressure on the stock will not transfer to the action and change POI. With the stock screw loose the action can shift if pressure is applied to it by the stock. that way there are no stresses on the action and in turn the barrel etc. Consistently no pressure. Everything free to move as it will. That way the scope will always stay in line with the barrel and nothing ever has stress on it.
Does that help?"