Portsmouth Coroner David Horsley has recorded a narrative verdict in the inquest into the death of Samuel Hatton.
Mr Horsley said the sailor had killed himself and had intended to do so. He made two recommendations to the Royal Navy following the death.
He said greater authorisation should be required before sailors were allowed access to the rifle rack. Sailor Hatton shot himself with a rifle. The inquest heard that a lock on the rifle store was faulty.
Mr Horsley also said the navy should adjust its personnel system. He said Sailor Hatton had been the wrong type of person for that sort of ship - a small ship, with a small ship's company.
Samuel Hatton, known as "Ricky" after the boxer, killed himself on board HMS Cattistock in 2010. The inquest heard he had been affected by the death of his friend Matthew Webster who had killed himself.
In evidence, the ship's captain, Lt Commander Charles Maynard rejected claims that the 20 year old Engineering Technician had been bullied by an un-named senior colleague, saying that banter is a natural state of affairs on a small ship and that he would have been aware if it was anything more.