Mark Robson (46), of Drummond Walk, will serve two years and seven months for his part in the plot, following hearing at Leicester Crown Court yesterday (Wednesday).
Joshua Mooney (25), of Millstone Lane, Syston, 26-year-old Leicester man Zunaid Bobat and a 17-year-old, also from the city and who cannot be named for legal reasons were also jailed.
A year-long investigation by officers from the East Midlands Special Operations Unit (EMSOU) resulted in the seizing of firearms, knives, cash and mobile phones.
An examination of the phones linked them to the supply of drugs in Melton, Hinckley and Leicester.
Det Insp Lee Hunt, the senior investigating officer. said: “The group had a plan in place to supply drugs across both the city and county.
“However, their actions were being monitored and they were arrested earlier this year.
“A search of their addresses confirmed what we believed to be true – that they were established drug-dealers.
“I hope that the people of Hinckley, Melton and the wider county can take some relief from the fact that these four people have now been brought to justice and are serving time in prison.
“We will always act on information regarding the supply and distribution of drugs and I would ask anyone who has concerns or believes they can help police to get in touch.”
The four were arrested in May and subsequently pleaded guilty to two counts of conspiracy to supply a controlled class A drug at hearings between August and October.
Bobat was jailed for six years and eleven months for the drugs offences and also a breach of a non-molestation order, while Mooney was handed a sentence of four years and 10 months.
The 17-year-old, who also pleaded guilty to one count of having an article with a blade or point, one count of possessing a prohibited firearm and one count of possessing ammunition without a firearm certificate, was sentenced to four years and 10 months in custody.