More than 30 children aged under 10 in England and Wales were issued with shotgun licences in the last three years, official figures revealed.
The statistics show 11 certificates were issued to under-10s last year, five in 2009 and 15 in 2008.
The figures were obtained by Labour MP Thomas Docherty, who has campaigned for a change in the law to set a minimum age for holding a shotgun licence.
Children are not allowed to use a gun unsupervised until they are 15, but the Dunfermline and West Fife MP said the rules were "really weak".
Mr Docherty said: "Society as a whole is deeply uncomfortable with the idea of a seven-year-old having access to a lethal weapon.
"I have not heard a single coherent argument for why a seven-year-old, who has no legal culpability, should be allowed to have unfettered access to fire a firearm."
Mr Docherty, who earlier this year launched a parliamentary bid to ban under-14s from holding a licence, said senior police agreed with the need for a minimum age.
The Association of Chief Police Officers had argued that 10 would be a suitable minimum age.
Mr Docherty said: "Do we have to wait until we get a tragic accident involving a seven or eight-year-old before we take action?"
The MP said he understood why people needed guns for land management and sporting purposes and stressed: "I'm not trying to ban it."