It is the most terrifying collection of weapons in Greater Manchester.
The Magnums, Uzis, Mach 10s and Kalashnikovs in this room could cause untold death and injury in the wrong hands.
Some have done.
For that reason, they are stored in a secret, nondescript location.
Once beyond the barrier, it takes three sets of doors, with three separate pass numbers, before you reach the armoury.
It is manned around the clock, with the bullets kept separately from the guns.
This is GMP's gun room - where weapons seized from the underworld are kept. They are stored so firearms officers can study them, and know how best to handle them.
We were given rare access to the facility as officers deal with a recent rise in gun crime. Weapons here have been seized in raids across Greater Manchester.
A terrifying, Israeli-made, Desert Eagle .44 Magnum, a 'Dirty Harry' Smith and Wesson Magnum, and a Chinese copy of the infamous AK47 assault rifle are just three of the 185 recovered weapons on a rack in the facility.
One amateur looking, tatty green weapon turns out to be a home-made machine gun constructed in the shipyards of Belfast.
It passed from a Northern Ireland para-military group to the streets of Manchester, fitted with a Thompson machine-gun magazine.
Uzi and Mach 10 'spray and forget' machine guns, and rows of handguns, including a West-German-made Carl Walther PPK - James Bond's weapon of choice - sit alongside antiques and curios in the arsenal.
The umbrella on the rack is actually a taser gun, the walking stick is a shotgun in disguise.
Then there is an item which looks like a biro - until you remove the tip and see the chamber where .22 bullets are placed. It was found during a cell search at Strangeways Prison.
Even 'novelty' weapons have dark histories.
A key fob gun, manufactured in Eastern Europe, was originally designed as a legal self defence weapon, before being adapted to fire a live round instead of a blank.
One GMP firearms officer told the M.E.N: "They came to our attention when a man bought one, but it didn't work because it had a safety mechanism.
"He went back to the fella he had bought it off, took him into the gents toilets in a club, and said 'this gun I bought off you doesn't work.' He put it to his head, twisted it through 190 degrees again, and inadvertently shot himself dead."
The 10ft square armoury holds 341 guns for issue to GMP firearms officers, as well as the confiscated horde.
Normally, seized weapons, once used as evidence in court, are taken under escort to steel works and melted down with scrap metal.
The firearms officer who takes them to the works has to watch for 20 minutes - once they have been placed in a scorching crucible - to be sure they are destroyed.
Once melted down they are turned into ingots and used in steel production.
Weapons of particular historical value - whether recovered or handed in under an amnesty - end up with museums.
The officer said: "Once recovered, tests are done on a weapon by the National Ballistics Intelligence Service based at Bradford Park. They identify the unique signature the weapon will leave behind on bullets fired from it. That is then recorded and stored on a national computer.
"The unique signature is [formed by] scorings and scratchings on the outer casing of the bullet that come from the barrel of the weapon.
"Forensic experts can then link a bullet to a weapon, and use of the same weapon can be collated. It is almost as unique as a fingerprint or DNA."
"Nine times out of ten guns will be destroyed", the officer went on. "If they are unique or significant, or we think our officers going through training can learn from it [they are kept].
"One of the regular jobs that firearms officers have to do is to go to a house to make a weapon safe once found.
"If say a new weapon comes in from Eastern Europe, and only a few have been picked up, our officers need to be aware how to make them safe, and dismantle them - so we will keep it for training.
"The last thing we want is for a a weapon that is unsafe to end up being handled by a civilian officer being transported, it gets dropped, we have a negligent discharge and someone gets injured."
The collection includes highly realistic paintballing weapons, and even a replica plastic gun with orange patches.
"Toy manufactures started to spray guns with fluorescent colours to make it obvious they were a toy. Then criminals said ' if we spray ours with car spray, the police will think it is a toy'. That is what started happening," the officer said.
Crucially, in Greater Manchester, after being reduced from from a high of 150 in 2007 to a low of 22 in 2013 the number of gun discharges rose to 59 last year, with 19 people being injured and one killed.
So far in 2019 there have been 22 discharges and five people injured.
While the number of gun crimes leapt from 430 in 2016 to 606, in 2017, in Greater Manchester, it dropped to 439 last year.
Meanwhile, in the West Midlands, which is a similar-sized force area, there were 672 gun crimes in 2017. The rise is national issue - not merely a local trend.
The biggest fear for police is innocents becoming casualties.
Det Supt Jon Chadwick, Head of Organised Crime, said: "People shooting guns in streets is a huge concern for people and communities.
"It is not a massive upturn in incidents, murders are still very low, the number of people being hurt remains about a third of the discharges, and most have a criminal history.
"But we are scared to death of people getting caught in the cross fire."
He has good reason to be.
The region has seen a number of high profile cases where totally innocent people have been hit.
In January 2014 Marie Calder, 56, suffered arm injuries after she and her son were shot in the car park of Gala Bingo in Harpurhey.
In October 2015 seven-year-old Christian Hickey and his mother, Jayne, were shot in the legs on their door step in Eccles. The gunman had come for Christian's father.
Dale Brierley , 34, was shot in June 2016 after nipping out to buy a carton of milk in a case of mistaken identity.
He was blasted in the chest near his then home in Little Hulton, Salford. He spent three days fighting for his life in intensive care.
In all these cases people were jailed.
But in another case justice has - so far - remained out of reach.
Innocent 20-year-old, Halton McCollin , call centre worker and keen amateur footballer, had no connection to crime whatsoever, but was shot dead in a Stretford takeaway after being mistaken for someone else.
In the years after his death, Halton's father, Halton Senior, has campaigned against gun crime.
He remembers clearly the last time he spoke to his son - on the night he died.
"He was due to come over to Bolton to my house to watch a football match on TV, but there was horrendous rain. I thought he has only been driving for a short amount of time, and whether he should be driving on the motorway.
"I was concerned about the weather. He said 'yes dad, I 'm going to have a takeaway and chill out'. Then I think he decided as he wasn't coming over he would see some mates after getting something to eat.
"Then he went to the takeaway, and that was the end of a beautiful life. Wrong place, wrong time."
"The hatred that I had at the time, I think that has ceased. But what I want know is justice. The burning resentment was stopping me from having a normal life."
Commenting on the rise in gun crime in the region he said: "It all comes down to people living in the communities affected. Police can only do so much.
"Gun crime and knife crime are spreading beyond the cities. There has to be a a closer bond between the police and communities. People have to be vigilant, and honest, and report what they have witnessed.
"If you see someone who is carrying arms, even if they are family members , friends, you can have a word with them, saying you need to hand that in."
