It was at the end of October last year that the police made a house search in the man's apartment after an alarm that there were explosives in the property.
An explosive device, weapons and ammunition as well as drugs were found at the scene.
Everything was seized and the 31-year-old was arrested.
Several involved
During the autumn, an extensive investigation was carried out and the case has grown.
Another four people were charged on suspicion of involvement in the handling of the explosive object.
The prosecutor wanted two of these to be sentenced to aggravated weapon crime and violation of the law on flammable and explosive goods and the other two to assist in these cases.
However, only one of those involved is convicted on these counts, a man in his 30s who is sentenced to one and a half years in prison for aiding and abetting the two crimes.
This was when he was the one who handed over the explosive to the 31-year-old.
The other three people are acquitted on these charges but sentenced to a daily fine for minor drug offenses.
Admits crime
The 31-year-old man who was responsible for the explosives admits the crimes.
In addition to serious gun crime and crime against flammable and explosive goods, he is also convicted of minor drug crimes.
The penalty for all crimes is imprisonment for three years and three months.