A Royal Marines reservist will be sentenced later for trying to sell a cache of stolen arms in an undercover sting.
Martin Shannon, 43, of Hythe, Southampton, took guns, ammunition, explosives and grenades from his base in Poole over four years and buried them in the New Forest.
He was snared by an undercover National Crime Agency officer who handed him £10,000 for the sale or loan of ammunition and guns at a meeting in a pub car park near Newbury.
Following his arrest, Shannon told officers he wanted to make money selling the guns to "Great Train Robber types" who would open safes in a "cloak and dagger" style before "running off into the sunset".
The cash-strapped defendant was suffering from post-traumatic stress disorder at the time and pleaded guilty to 15 offences at the Old Bailey.
The Ministry of Defence launched its own inquiry after supplies went missing from the Poole base.
Shannon had joined as a Royal Marines reservist in 1996 and was also a commercial diver and HG driver.
He was questioned by MoD investigators after an assault rifle and self-loading pistol went missing from the base in October 2012 but he denied involvement.
On the evening of September 1, he met the undercover NCA officer in the Chieveley area of Newbury, and brought ammunition, grenades and pyrotechnic munitions which he sold for £5,000.
He also agreed to lend the officer a Diemaco assault rifle and Sig Sauer P226 handgun for an extra £5,000, handing them over with a sawn-off shotgun.
Shannon told the officer the stash was "military grade" and the grenades were "big stuff".
One of the guns was loaded when the defendant showed it to the officer, the court heard.
Shannon told the officer the deal was about "him wanting to make some money". He described himself as "old school", "old fashioned" and "loyal", and was "happy to be part of a team".
After the meeting, he was tracked to a supermarket in Winnall, near Winchester, where officers moved to arrest him safely.
A search of his home uncovered 500 rounds of ammunition and a stick of plastic explosive. Some of the bullets were hidden inside a Kenco coffee jar.
Following his arrest, Shannon was asked if he had any issues and he said it would "all come out in the wash", the court heard.
In an interview, he explained how he had picked up and kept the guns which were meant for use on a training range.
The self-confessed "hoarder" said he stored them in watertight containers buried in the New Forest.
Shannon admitted there was another weapon buried in a hide and took investigators to the spot. Specialist officers later discovered a bolt-action shotgun buried near a train track.
Asked in the interview why he did it, Shannon said he thought the buyers would be stealing from drug dealers or were "Great Train Robber types" who were after money and did not hurt people.
He admitted all the charges including transferring a prohibited weapon, having explosives, possession of ammunition, transferring prohibited ammunition and possession of a firearm without a certificate.
Judge Richard Marks QC will sentence Shannon at the Old Bailey from 2pm.