An ex-RAF engineer has been jailed a plot to buy two hand grenades.
Alex Piatt-Green, 52, used an encrypted app to order the weapons for delivery to his home in Redditch, using £500 in bitcoin, the Old Bailey heard.
He told the court he was under the influence of drugs at the time, but the court heard he planned to buy more weaponry from his source in the US.
Piatt-Green was jailed for six years after pleading guilty to attempting to possess an explosive substance.
Mr Justice Jeremy Baker dismissed the defendant's claim he was acting out a "fantasy", saying the purchase was in the "context of serious organised crime."
The court previously heard the former mechanic used the Telegram app as he made an arrangement to buy two fragmentation grenades late last year, to be delivered in January.
He had told the seller: "If everything goes well I will be back for handguns and rifles," the court heard.
The consignment was intercepted by US authorities and two M67 hand grenades were found hidden inside legitimate goods.
A dummy parcel was arranged by the UK's National Crime Agency to replace the delivery while Piatt-Green was kept under surveillance.
Prosecutor Peter Ratcliff told the court the defendant had had weapons training and had handled munitions while working in the military.
Giving evidence, Piatt-Green said: "It is wrong and it is the thrill of doing something very wrong that will magnify with my current state of mind and my use of drugs and alcohol. It was extremely thrilling."
He told the court the messages with the seller were "all part of the pantomime" and he had dumped the delivery in a bin near his home.
As he passed sentence, Mr Justice Baker told Piatt-Green: "The prosecution do not suggest you intended the grenades for terrorist purposes or to provide them to those who would provide them for those purposes.
"However, the prosecution did not accept your basis of plea and said it would be open to the court to determine you were working as part of a group seeking to acquire dangerous weapons."
He said the defendant had committed the offence "as part of a group" and that it involved the use of encrypted messages as part of a deception.
Piatt-Green was also handed a two-year licence extension for after he is released.
Rick Mackenzie, NCA operations manager, said: "Hand grenades are designed to cause indiscriminate harm to a large number of people and the devastation that these weapons could have had in our communities cannot be understated.
"The NCA is committed to protecting the public from criminals who seek out firearms and explosives."