How does a Nerf gun or a nail gun meet the 500fps and 4.2fpe to be considered technically a firearm? I don't think they do.
I'm using the language of the law. Being a firearm does not have anything to do with the 500fps condition. i.e. the firearm act only regulates a specific subset of firearms. There are plenty of unregulated firearms, such as Nerf guns, and pen tubes used to fire spitballs, and, for example: Crosman Full-Auto A4-P BB Pistol w/Red Dot Sight [
https://www.airgunsource.ca/us/crosman-full-auto-a4-p-bb-pistol-w-red-dot-sight.html]. There are also "firearms regulated by the Firearms Act", i.e. these are the "real guns according to Canadian law".
Feels silly, but it is what it is. Here are some more details:
“Firearm” means a barrelled weapon from which any shot, bullet, or other projectile can be discharged and that is capable of causing serious bodily injury or death to a person, and includes any frame or receiver of such a barrelled weapon and anything that can be adapted for use as a firearm.
How does the Crown prove that it’s a firearm?
As defined, a firearm must be capable of causing serious bodily injury or death to a person. In order to determine this the Firearms Section of the Forensic Laboratory for the Royal Mounted Canadian Police conducted a study to determine at what muzzle velocity a BB fired from a gun would penetrate a pig’s eye. While not identical to the human eye, it’s was a close approximation. BBs were shot at a distance of 10 feet into the corneas of pig eyes with a pump-action BB gun.
They published their findings in the article “Velocity Necessary For a BB To Penetrate The Eye: An Experimental Study Using Pigs Eyes.” Their conclusion was “due to the nearly identical size and anatomy of the human eye to the pig eyes used in this study, it is felt that 264 ft/sec is a reasonable approximation of the velocity needed to penetrate the human eye.”
They found that at this velocity, the BB would penetrate the pig’s eye 50% of the time. Lower velocity BBs would still sometimes penetrate the eye, while sometimes a higher velocity BBs would fail to penetrate the eye.
In cases that are alleged to involve the use of a firearm, the investigating officer will seize the weapon for forensic testing. It will be sent to a lab with a request to test whether the firearm is capable of firing, and if not, what steps need to be taken to make it capable of firing, along with an assessment of the muzzle velocity expressed in feet per second.
ref:
http://www.winnipegcriminaldefencelawyer.ca/firearm-defined