The gang "bullied" the 20-year-old into the back of a van before threatening him with a shotgun, beating his knees with a mallet and stunning him with a Taser-style weapon.
Luton Crown Court heard the gang took him captive as revenge for the apparent theft of cannabis worth Â£60,000.
The gang admitted a range of offences and received sentences up to 20 years.
The court heard the kidnap took place in Luton on 20 June last year.
More on this story and other Bedfordshire news
They bundled the man into the van in Downs Road before driving to an address in Ashburnham Road.
During his imprisonment, the gang put a live shotgun in his mouth, stubbed out cigarettes on his arm and beat him with a knife.
Ransom calls were made to the victim's relatives, and one defendant also threatened to rape him.
The following morning, the victim was abandoned and left tied to the metal gate of a farm near Kensworth. He freed himself and made his way home.
The court heard the gang believed two brothers had stolen cannabis from them, and targeted the victim - the boyfriend of the two brothers' sister.
Six men who kidnapped a man at gunpoint before torturing him for 30 hours have been jailed.