Tajudeen Anjorin, 36, of Helston Gardens was sent down for 11 years for supplying heroin and Damien Cadogan, 28, for 10 years for similar drug offences and possessing a handgun found in the garden of his Anson Crescent home.
Reading Crown Court was told police smashed the gang in February last year when officers arrested four Welsh men whose car was stopped at the M4 Membury services as they returned home to Newport after visiting Cadogan's home in Whitley. They found half a kilo of heroin worth between £75,000 and £100,000 in the car.
Prosecutors said Cadogan had been storing the heroin with the help of Anjorin and when officers searched his garden they found the gun wrapped in a kitchen towel from the house.
Cadogan and Anjorin denied the charges but, with Nicholas Somers, 23, and 22-year-old Tobias Mills, both from Newport, were convicted after a six week trial. Somers was jailed for 5½ years and Mills for 2½.
Dominic Isaacs, and Bradleigh Scawthorn, both 21 and also from Newport, admitted supplying heroin. Isaacs was jailed for nine years and Scawthorn, who also admitted a charge of possessing Class A drugs with intent to supply, for eight year and 10 months.
Baljit Ubhey, Thames Valley chief prosecutor, said the case was cracked after a "thorough" police investigation uncovered regular telephone contact between Isaacs in Wales and Anjorin and Cadogan in Reading.
Isaacs and Scawthorn were tracked travelling to Reading on several occasions before last year's police swoop, and Anjorin and Cadogan had driven down the M4 to Newport.
She said: "It is believed Anjorin was in part behind the supply of the drugs to the Welsh contingent, who would have supplied it on down the chain in Wales.
"Cadogan was the middle man, and had access to a gun, as people involved in the drugs trade often do, to enforce deals, or to protect themselves from others interested in operating in the market of class A drugs."
She added: "These lawless men have been removed from society for a substantial period, and the public has been made safe from their dangerous, harmful and life destroying activities."