The death of soldier Private Sean Benton at Deepcut Barracks in 1995 was caused by "self-inflicted" gunshot wounds to the chest and has been formally recorded as a suicide.
Coroner Peter Rook QC was concluding at an inquest at Woking Coroner's Court, where he said:
"I'm satisfied that the fatal wounds were self-inflicted."
He said the first round injured the soldier, but that a second round - fired by Pte Benton when two officers arrived at the scene - proved fatal.
Notes to his friends and family were found afterwards.
Summing up, the coroner said:
"There was ample evidence available to those at Deepcut that Sean was vulnerable."
Pte Sean Benton, 20, was found with five bullets in his chest at the Surrey base in June 1995, shortly after he had been told he was to be discharged from the military.
He was the first of four soldiers to have died there between 1995 and 2002 amid claims of bullying and abuse.
Privates Sean Benton, Cheryl James, Geoff Gray and James Collinson all died from gunshot wounds at Deepcut. (Image: PA)
Mr Rook described a litany of failures with the original investigation into Pte Benton's death.
He said he was hampered by a failure to preserve evidence, poor photographs of the scene and a lack of scrutiny of eyewitness accounts, among other things.
He said: "Even by the standards of 1995, the investigation into Sean's death was woefully inadequate.
"My own investigation has been greatly hindered by the inadequacies of the original investigation."
The court heard how Pte Benton had changed in attitude during his time at the barracks.
The coroner said: "A common theme from former trainee colleagues is they observed a change in him ... he was not as bubbly as he used to be."
A witness previously told the inquest: "Sean was initially happy and as time went on he laughed less ... he just stopped caring."
This included a change in his demeanour and his appearance after he failed a military driving test, the court heard.
Fellow recruits described Deepcut as an "oppressive place".
Mr Rook said: "It was not just those at Deepcut that noticed a change.
"His mother remarked to police that he phoned home less often and described Deepcut [in February 1995] as 'boring and repetitive'."
The court also heard how the conduct of Sergeant Andrew Gavaghan, one of Pte Benton's instructors, was key in the investigation into the young man's death.
The former Deepcut instructor was alleged to have bullied Pte Benton.
Witnesses have told throughout the months-long hearing of alleged physical and verbal abuse from Sgt Gavaghan, who was said to have an "alter ego" which he referred to as his "twin brother".
Sgt Gavaghan has denied allegations of abuse.
Speaking outside Woking Coroners Court, Pte Benton's sister, Tracy Lewis said her family would be asking the police to open a criminal investigation:
Brigadier Christopher Coles, Head of Army Personnel Support Group, spoke outside the court and said "the Army deeply regrets" Private Benton's death:
The inquest, which began in January, was 23 years after the first hearing, held just a month after Pte Benton's death.
Members of the soldier's family, including sister Tracy Lewis and his twin brother Tony Benton, were among those in court as the coroner began his ruling.
Pte Benton's death was originally recorded as suicide but his family campaigned for a full investigation following allegations he suffered prolonged physical and psychological bullying.