The deceased, identified only as Virender, sustained a bullet injury while handling firearms on duty at 'INS Kalinga' on Sunday night, according to a Naval release.
He was shifted to a hospital where he succumbed to injury. Police were informed and a Board of Inquiry has been ordered into the incident at Naval establishment, it said.
Virender, a bachelor, hailed from Jhajjar town in Haryana and had joined the Navy five years ago.
However, Bheemili Police Station Inspector S Appala Naidu, who described Virender as a marine commando, said he shot himself in the head with the pistol allotted to him.
No suicide note was found from the spot, he said.
Police said Virender was not in his uniform at the time of the incident, after which he was taken to a corporate hospital, where a medical team declared him brought dead.
Police have filed a case under CrPC Section 174 (suspicious death) and started investigation from various angles.
Photograph used only for representational purposes