"The use of force has been entirely disproportionate to any perceived threat."
Outside court Mr Bradley's family welcomed the verdict.
His brother Danny, who has long campaigned for a fresh inquest, said he had faced a threat from the IRA in Londonderry to pursue the inquest.
"I am happy with the verdict, very happy with the verdict," he said.
"As the judge said, it's 47 years [later] but it's a lot better than the last [inquest] verdict. I am happy that I went forward, even with IRA threats, and got this situation heard today. "
The findings of the Inquest follow fresh hearings that lasted 12 days last year.
Legal representatives from the Ministry of Defense (MoD) have asked for the last 47 years, which Mr Bradley was armed when they opened fire on the Bishop's Field of Creggan.
This claim has been denied by the Bradley family over the decades. The family also claimed that Mr Bradley was interrogated and tortured by the police before he died.
The killing took place amidst the British Army's move into nationalist 'no-go' areas in the Creggan, Bogside and Brandywell areas of Londonderry, called Operation Motorman.