A thief broke into a garage and made off with the air-rifle and a bottle full of ammunition.
Owner Dave Chandler, aged 32, who holds a special licence, is desperately worried the weapon could be used to threaten or injure someone.
He has offer
ed a £100 reward for the return of the replica gun.
Although the rifle is used as an airgun, it can fire ball bearings at up to 400 rounds per minute at speeds of up to 250mph.
Mr Chandler, who lives in Bracklesham Road, Hayling Island, bought the £300 weapon as his hobby is Airsoft skirmishing – an organised shooting game played in fields and woods that is similar to paintballing and uses airguns that fire plastic projectiles.
He said: "I am keen to get my gun back into safe and responsible hands.
"It could easily blind someone or could kill people and animals.
"Ultimately, if a foolish person is wielding it in public, the armed police might shoot them on sight, as it looks and feels very authentic."
The burglar raided the garage at Mr Chandler's home while the family was out sometime between 8.20am and 10.20am or 1.55pm and 3.20pm on October 21.
As well as the airgun the thief took Mr Chandler's six-year-old son's radio-controlled car - an Alfa Romeo 155 Touring Car model - a Sony Nav-U NVX P1 Satnav in its original box, and a Sony CDX F7500 car stereo.
Mr Chandler added: "If it had been kids, I think the airgun would have turned up by now.
"It's just crazy why they would have taken a remote-controlled car and an airgun."
PC Chrissie Broughton urged people to contact police if they knew of the gun's whereabouts.
She said: "These items are not illegal to own in the UK, though it is illegal to have them in a public place at any time.
"We would like to reassure the local community that, while this plastic replica can fire small projectiles which can cause injury, it is an imitation firearm.
"Every effort is being made to find the person responsible and ensure that this replica is not used in the commission of a criminal offence."
Anyone with information about the whereabouts of the replica AK-47 or the burglary should contact the Waterlooville Priority Crime Team on 101 or Crimestoppers anonymously on 0800 555111.
