In connection with a car being shot at in the Kronoparken area this summer, a mobile phone from one of the Karlstad residents was confiscated.
A man was arrested later in the summer on Rud after a loaded pistol was found in a bush nearby.
The investigation eventually led to a house search in Stockholm where several weapons and drugs were found.
Arms shops from Kumlaanstalten
The two Karlstad residents are sentenced to 2 years and 6 months in prison for aiding and abetting a felony and 9 months in prison for a felony.
Several of the people were inside the Kumlaan institution at the time of the gun crime, but are said to have run gun deals from the inside.
All seven convicted persons, six men and one woman, deny any wrongdoing.