The Liberals say their proposed definition of a prohibited assault-style firearm applies only to guns that belong on the battlefield.
But Conservative MPs are continuing to insist the federal move would outlaw many ordinary hunting rifles and shotguns.
The Liberal government wants to include an evergreen definition of a prohibited assault-style firearm in gun-control legislation being studied by the House of Commons public safety committee.
The measure, introduced Tuesday during clause-by-clause review of the bill, would build on a federal regulatory ban of many types of firearms in May 2020.
Among other technical specifications, the definition includes a centrefire semi-automatic rifle or shotgun designed to accept a detachable magazine that can hold more than five cartridges.
At a committee meeting today, Conservative MP Raquel Dancho said the definition amounts to the most significant hunting rifle ban in the history of Canada.