Darren Mentore, Clinton Officer and Jamal Shaka Smith were handed prison terms of 12, 11 and six years respectively at the city's Crown Court on Friday.
The three men were part of a network of 17 individuals who worked for the 'untouchable' Nosakhere Stephenson, the head of the crime group, who was jailed in November 2015.
They were all caught in a major undercover operation which saw the the recovery of a of eight firearms, including a MAC-10 machine gun and pump action shotgun found buried in a garden in Aston, as well as thousands of rounds of ammunition.
The sting, which was set up in summer 2014 and carried out by West Midlands Police's Serious and Organised Crime Unit with support from the National Ballistics Intelligence Service (NABIS)., involved surveillance over many months and saw detectives intercept the movement of weapons from suppliers to buyers on five separate occasions.
Although Stephenson was never caught in possession of the guns, phone records linked him to each deal and every other person in the conspiracy - including his right-hand man, Sundish Nazran.
Nosakhere Stephenson, 41, of St Michaels Road, Handsworth, Birmingham, pleaded guilty - jailed for 16-and-a-half years in November 2015
Sundish Nazran, 32, of Nijon Close, Handsworth, Birmingham, pleaded guilty - jailed for 13 years in November 2015
Joynal Abdin, 26, of Hanover Close, Aston, Birmingham, found guilty following trial - jailed for seven years and three months in November 2015
Fitzroy Ducram, 50, of no fixed address, pleaded guilty - jailed for seven years four months in November 2015
Mohammed Fedar, 27, of Westfield Road, Smethwick, pleaded guilty - jailed for four years four months in November 2015
Amar Ghalib, 32, of Davey Road, Perry Barr, Birmingham, pleaded guilty - jailed for four years 11 months in November 2015
Rowan Gul, 33, of Reginald Road, Alum Rock, Birmingham, pleaded guilty - jailed for 12 years three months in November 2015
Usman Hussain, 31, of Brays Road, Sheldon, Birmingham, pleaded guilty - jailed for five years in November 2015
Ifran Hussain, 25, of Underwood Road, Handsworth Wood, Birmingham, pleaded guilty - jailed for 10 years 10 months (also for possession with intent to supply Class A) in November 2015
Joga Mattu, 31, of Cranbrook Road, Handsworth, Birmingham, pleaded guilty - jailed for five years in November 2015
Louis McDermott, 36, of no fixed address, pleaded guilty - jailed for nine years four months in November 2015
Darren Mentore, 35, of no fixed address, found guilty following trial jailed for 12 years in January 2016
Mohammed Selu Miah, 24, of no fixed address, pleaded guilty - jailed for 13 years (also for possession with intent to supply Class A) in November 2015
Janed Mohammed, 21, of Dibble Road, Smethwick, pleaded guilty - jailed for four years six months in November 2015
Clinton Officer, 32, of Wallflower Street, Shepherds Bush, London, found guilty following trial jailed for 11 years in January 2016
Jamal Shaka Smith, 35, of Ladywood Middleway, Birmingham, pleaded guilty jailed for six years in January 2016
Mohammed Ullah, 19, of Frederick Road, Aston, Birmingham, pleaded guilty - jailed for five years in November 2015
Theodore Junior Wiggan, 28, of Scaffle Way, West Bromwich, pleaded guilty - jailed for 10 years in November 2015
Between them, the pair would source antique guns and arrange for ammunition to be specially made to fit the weapons. They would then be sold on to criminal gangs for considerable profit, at around £3,000 apiece.
Stephenson, Nazran and 13 others admitted conspiracy to transfer guns and ammunition between March 4, 2014 and January 17, 2015, while three others were found guilty following a trial.
Mentore, Officer and Smith were the last to be sentenced. The other 15 were jailed on Thursday 26, and Friday 27, November 2015.
Speaking in November, Chief Inspector Simon Wallis, from West Midlands Police's Serious and Organised Crime Unit, said: "Stephenson or 'Nosa' was widely-regarded as the untouchable 'Godfather' of the Burger Bar gang but as this case goes to show, nobody is above the law.
"He tried his best to distance himself from his accomplices but through undercover surveillance work and extensive investigations into phone records we were able to prove he was at the centre of this highly-organised and extremely dangerous gun supply network.
"Today's result is fantastic because we've put some prolific criminals behind bars who have been responsible for bringing dangerous weapons to our city. It is no exaggeration to say each and every gun or bullet that we've seized represents a life potentially saved."
Chief Inspector Wallis added: "There aren't a large number of guns or ammunition on the streets of Birmingham which is why this haul is particularly significant.
"We've made real progress over the last decade and cut gun and gang related crime massively. However, recent shootings in Birmingham - some of which have resulted in people losing their lives - highlight why it's important there's no let-up in our effort to rid the region of weapons.
"If you're involved in the illegal supply of firearms in the West Midlands, you're risking a very hefty prison sentence and it's only a matter of time before my team catches up with you."
West Midlands Police and Crime Commissioner David Jamieson said in November: "It is totally unacceptable to carry or trade weapons and those doing so will be targeted by West Midlands Police and brought to justice.
"Gun crime and getting weapons off the streets is very important and is a priority of mine. I want to reassure communities that I will not leave a stone unturned in the pursuit of those who carry and trade deadly weapons.
"Weapons like the ones intercepted have only one purpose, to wound or kill. Getting these weapons and ammunition off the streets and breaking-up organised gangs is important work in making the streets of the West Midlands safer.
"No-one is above the law or untouchable. I have made the targeting of gangs and individuals carrying and trading deadly weapons a priority of the police. In my role as Police and Crime Commissioner I will ensure West Midlands Police continue to focus on this issue."
The National Ballistics Intelligence Service (NABIS) provides a dedicated forensic service to analyse ballistic material from across the UK. NABIS forensic hubs utilise cutting edge technology to connect incidents nationwide where ballistic material has been recovered. NABIS then shares the forensic analysis information to create a national picture that links the criminal use of firearms across the country.