After reading the various news items in which the idea of a Quebec-only long gun registry has been floated, I have been considering the fascinating constitutional implications of such a move.

As firearms owners are well aware, the constitutional challenge against the federal Firearms Act on the grounds that it encroached on provincial jurisdiction ultimately failed at the Supreme Court of Canada.
In Reference re Firearms Act, [2000] 1 S.C.R. 783,  Alberta, and the provinces who supported the challenge against the Firearms Act, argued that the law was truly regulatory in scope and therefore fell under the provincial jurisdiction to legislate in regard to “property and civil rights”.
However, a unanimous Supreme Court found that the federal gun control scheme, including the Canadian Firearms Registry, was a matter which fell under the federal criminal law power. The court held that the “pith and substance” of the Act related to “public safety” which was within the criminal law power.
Accordingly, Alberta’s  challenge failed and the rest, as they say, is history.
Quebec’s recent move (or non-move, considering that no legislation has been passed or even tabled at this point) would seem to revive the debate which was apparently resolved by the Firearms Reference. The irony is, of course, that this time, Quebec (and any other supporters of gun control) would have to take Alberta’s position, which was resoundingly defeated at the Supreme Court of Canada.
Of course, Quebec could argue that a registry-only program was not truly criminal law, merely the regulation of property and civil rights. However, depending on the penal nature of the legislation, this claim may not pass muster. Considering that the main indicia of criminal law are penal purpose, prohibition and penalty, the Quebec law may indeed constitute criminal legislation and therefore be ultra vires (beyond the powers of) the provincial government to enact.