Moynul Haque admitted fraudulent evasion by arranging for the barrel and slide of a Glock 9mm parabellum self loading revolver to be sent to him from the USA, when he appeared at Wolverhampton Crown Court.
The offence was committed between April 1 and May 10 of last year when he placed the order over the internet with a distributor in America.
The items were intercepted by customs officers on the other side of the Atlantic who alerted the UK authorities, prompting the arrest of 21-year-old Haque from Brasshouse Lane, Smethwick.
Mr Alex Warren, prosecuting, told the court: "He appears to be a reclusive person. There is no reason to suspect he is involved in any criminal organisation or has terrorist links."
The defendant, a factory operative living with his parents, brothers and a sister, was remanded on bail for a pre sentence report to be prepared.
Judge Kristina Montgomery QC warned Haque: "You must be entirely open with the probation service as to why you ordered this over the internet and what you intended to do with it."
"At the moment I have no view as to what the right sentence is."
No further details were given to the court but the case is expected to be opened in full at the defendant's next appearance scheduled for June 28.