Impossible to answer without knowing if it is a rifle or shotgun.
I do not think Mossberg made a 220K. The New Haven 220K (single shot bolt action 22) cross references to the Mossberg 320K. Value is around $100-$125. Excellent first rifle for a new shooter.
50-125 USD
$50-$100
My cross reference for that model shows it as a Mossberg 500. Those were not single shot firearms.
No. Its magazine holds 2, so in all, its a 3-shot.
10-125 USD depending on condition
50-300 usd
mossberg
50-150 USD
what is the value of a 1945 single shot 22
75-225 USD
75-250 US Dollars