The number of military-style firearms that can be temporarily jury-rigged to become automatic weapons has increased "dramatically" in Canada over the last decade — and so has the public-safety risk.

That's the stark conclusion of an internal RCMP laboratory report on improvised methods for upgrading semi-automatic weapons, and for illegally altering magazine clips to allow for rapid continuous fire.

The lab report notes that Criminal Code regulations designed to thwart makeshift upgrades may not apply to newer generations of weapons, creating a legal void.

RCMP internal report warns of firearm conversions to automatic1:34

"The restricted and prohibited firearm provisions of Criminal Code regulations were last updated in 1995, and there are presently numerous models of military and paramilitary firearms on the Canadian market which are outside the scope of the Criminal Code regulations, many being non-restricted in classification," says the 15-page report.

"The Canadian introduction of new types of military and paramilitary firearms not mentioned in the Criminal Code regulations, nearly all with large capacity magazines sizes, started circa 2005 and has accelerated since."

"The public safety threat posed by improvised conversion to full automatic fire has correspondingly increased."

Ralph Goodale

Public Safety Minister Ralph Goodale will be reviewing Canada's gun legislation to restore decision-making about restricted weapons to the RCMP rather than leaving it to cabinet. (CBC)

A heavily censored version of the internal report, dated November 2014, was obtained by CBC News under the Access to Information Act.

CBC News has previously reported on the RCMP's concerns about improvised assault-weapon upgrades, an issue raised by RCMP Commissioner Bob Paulson directly with then public safety minister Steven Blaney last year. But the detailed Mountie lab work documenting the issue was released only in the last week.

Last summer, Blaney rejected legislative changes to close any regulatory gap, saying the current law was sufficient. The Conservative government also passed Bill C-42 giving cabinet — not the RCMP — the final say about which weapons to restrict or ban, after the Mounties were slapped down for trying to get a popular semi-automatic withdrawn from Canada.

Some rifles could be banned

But the new Liberal government has promised to "put decision-making about weapons restrictions back into the hands of police, not politicians," raising the possibility the RCMP may yet be able to get some semi-automatics taken off the market.

A Mountie spokesman, Sgt. Harold Pfleiderer, would not say whether the RCMP is pressing the new Public Safety Minister Ralph Goodale to act on the issue. "The RCMP does not comment on the advice it provides to the minister," he said in an email.

A spokesman for Goodale reiterated the Liberal government's commitment to get "assault weapons off our streets," but said consultations are needed first.

'We will work ... to move forward on this commitment.' –Spokesman for Public Safety Minister Ralph Goodale

"We will work with all levels of government, our stakeholders and the Canadian Firearms Advisory Committee to move forward on this commitment," said Scott Bardsley.

Among the Liberals' election commitments is to broaden membership of the firearms committee to include representatives of women's groups and public-health advocates. Critics have said the committee is stacked with gun proponents.

The RCMP lab tested 11 models of rifles and one pistol, including the weapon used by Marc Lepine in the 1989 Montreal massacre and the semi-automatic used by Justin Bourque in the 2014 Mountie shootings in Moncton, N.B.

The testing was prompted by Bourque's statement to police that he had considered using an improvised technique to turn his rifle into an automatic weapon.

The report says more than 1,200 test shots were fired between July and November 2014, using a technique that is "widely reported on the internet complete with installation and fitting instructions." The name of the technique is blacked out in the documents, but has been known in gun circles for decades, and information about at least one other technique also circulates.

New firearms on market

The Criminal Code regulations in the 1990s effectively protected against any upgrades "by taking the firearms most practical for conversion to full automatic fire off the civilian market," says the document, authored by Murray A. Smith, manager with the RCMP Canadian Firearms Program.

"Thus, the public safety risk posed by improvised conversion techniques was largely negated and rendered moot, and not requiring much police attention."

But the proliferation of new firearms since 2005 has increased the risk to the public, augmented by the availability of new magazines.

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RCMP Commissioner Bob Paulson alerted then public safety minister Steven Blaney last year to potential legislative gaps in Criminal Code gun provisions. (Sean Kilpatrick/Canadian Press)

"Large capacity magazines are widely available for the military and paramilitary firearms, and although limited in capacity by law and generally reduced to five shots by a pin or similar modification, the original capacity is typically readily restorable."

"The materials required for improvised full automatic fire are ordinary everyday products."

Upgrading any weapon to fully automatic status is clearly prohibited by Section 102(1) of the Criminal Code, with prison terms of up to 10 years. But Smith's report raises questions about the current effectiveness of 20-year-old Criminal Code regulations as they apply to newer weapons shown in lab tests to be "amenable to the improvised full automatic fire technique."

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Evidence in Justin Bourque case released3:42