An 18-year-old man was arrested and component parts of a firearm found after police surrounded a house in Seacombe on Monday afternoon.
Detectives from Merseyside Police’s Matrix gun crime unit, responding to intelligence, recovered the magazine of a firearm from an address in Palatine Road after conducting a thorough search.
The magazine is being examined by forensic experts.
The 18-year-old was arrested on suspicion of possession of a firearm without a certificate. He has been released on bail pending further enquiries.
Superintendent Richie Davies said: "Information from the public is vital for us in the fight against gun crime and I would appeal to anyone who has information about where guns are being stored, or who is using them to call Crimestoppers anonymously."
Anyone who has any information can call Matrix Serious and Organised team on 0800 230 0600 or Crimestoppers, anonymously, on 0800 555 333.