The police department that returned the Plymouth gunman's shotgun to him weeks before he killed five people does not have enough staff, a senior officer has said.
Devon and Cornwall Police seized Jake Davison's shotgun in 2020 after he assaulted two teenagers in a park but it was returned to him shortly before the rampage two years ago.
Chief Superintendent Roy Linden told an inquest that the force gets 3,000 applications and renewals for shotgun and firearms licences every year and had the most licence holders in the UK.
Asked if the force, which he revealed had more than 30,000 shotgun licence holders and 11,132 firearms certificates in 2017 at the time Davidson applied for his, had enough staff to deal with that number, he said: "The simple answer is no."
He also admitted a backlog at the force at the time had "probably increased now".
Mr Linden's comments came as an image of the pump-action shotgun used by Davison, 22, was shown at the inquest on Thursday.
He shot dead his mother, Maxine, after a row at their home in August 2021 then wandered out into the street and killed Sophie Martyn, three, her father Lee, 43, Stephen Washington, 59, and Kate Shepherd, 66, in the Keyham area of Plymouth.
Davison, an apprentice crane operator, then turned the black Weatherby pump-action shotgun on himself before armed police officers reached him.
The inquest heard Davison applied for a shotgun certificate in July 2017.
He was issued a certificate, which was valid for five years, by Devon and Cornwall Police in January 2018.
Two years later, the force revoked the licence and seized his shotgun after Davison assaulted the teenagers.
The licence and weapon were returned to him in 2021, weeks before the killings.
The inquest was told that returning a licence after it has been revoked is classed as a "high-risk decision" in guidance issued to police in 2016.
Giving evidence, Superintendent Adrian Davis, a firearms licensing manager at Warwickshire Police, said these decisions should be conducted by a specialist licensing manager or a senior officer in certain circumstances.
He said he had 36 years experience in clay pigeon shooting and had only seen that type of shotgun used on one occasion.
Supt Davis said that Davison would have used a standard form used by forces across the country to apply for his licence and would have had to disclose any medical conditions and convictions, as well as providing a person to act as a referee.
The inquest heard Davison declared that he had autism on his application and gave consent for his GP to share information with police about his medical history.
However, Davison's GP refused to provide an opinion to police on whether he should be issued with a shotgun certificate.
Supt Davis confirmed there was "no requirement" for a GP to provide a report for an application at that time, or even for officers to contact a GP.
However, he told the inquest that officers should use "professional curiosity".
Supt Davis said the "vast, vast majority" of those with shotgun licences "pose absolutely no danger whatsoever to public safety or to the peace".
Ch Supt Linden, addressing the families at the inquest, said the victims had "needlessly lost their lives".
"It is our intention that this tragic incident will serve to drive improvements in firearms licensing both in Devon and Cornwall and nationally," he said.