That isn’t a firearm. That, like air guns, doesn’t fall under gun control laws.
But blowguns simplify the issues that gun control raises, and makes it easier to talk about the effects. Well, that and blowguns are completely illegal in California, unless you are a vet or animal control officer.
Now, if you looked at the above picture, the blowgun itself is just a tube. Not even a tube that needs to withstand pressure like a firearm, but a basic tube. All it needs to be is reasonably straight.
Then, you take a dart, put it in one end, and blow hard into that end.
To make a blowgun, you take a piece of straight pipe, like metal electrical conduit, pvc pipe, and make sure it is cut short enough that it doesn’t sag under its own weight. That is all that is required.
This is from the blowguns forum, and is a homemade Fukiya style dart. Fukiya is they style of blowgun and dart used for official USBA and IFA competition. For those who don’t know, IFA is the main governing body for competitions.
But look closely at that dart. It is a stun dart, made from a rolled paper cone and a nut. By rolling a paper cone around something like almost any nail you made a sharpened dart that can be used to take small game.
It isn’t like a firearm, which frequently requires some machining work or some harder to find component, a blowgun can be made by going to a hardware store for a box of nails and a pipe and then stopping at an office store for a box of paper.
To enforce the ban and prevent people making one, they would need to prevent people from buying paper, cotton balls and rubber discs as those are used to seal the breech of the blowgun. They would need to ban nails and nuts, as those are used to make the head of the dart. They would also need to ban wire, as that can be cut down and sharpened to make a point.
All sorts of straight rigid tubing would need to be banned. You would not be allowed to do any home repair project if it involved plumbing, and would be forced, by law, to hire a certified contractor. You could make one out of the scrap and waste pipe, or the pipe that was removed, so they would have to ban people doing any sort of work on their own plumbing.
If you have copper pipes, and one leaks, you would be required by law to hire a contractor and would be punished by law if you did anything to work on the pipes, to prevent you from taking some of the pipe and blowing a dart through it.
A rule of thumb heard sometimes when blowgun hunting is that a dart is good for an animal up to ten times its weight. This means a blowgun is best for small animals, like mice, rats, squirrels, and other small critters.
Things like ducks may not exactly be affected much by the dart. Sorry, I am not posting the picture from the link, as it is a duck with a wire dart in its head, but it is walking around and is not exactly affected by the dart lodged in its skull. That incident happened in California, where blowguns are supposed to be illegal. Then again, most people are completely ignorant of that law, but trying to buy a blowgun from a reputable source will tell you that they will not sell to California.
There is the worry about poison darts, but that is more dangerous to the user. Most poisons are either: illegal to get/effectively impossible to get or ineffective.
Things like poison dart frogs are used to take down monkeys in the rainforest. However, the dosage must be remembered. If a monkey and a human have the same dosage tolerance (say, 1 gram of poison per Kg of body mass) then the 5Kg monkey only needs 5g of poison, which will not kill the 50Kg human.
However, if monkey was replaced in that example by something like a deer, which on the large side of things a white-tail deer can weight 130Kg, and would require 130g of poison, more than enough to kill the 50Kg human. In other words, if the animal is near the same mass as a human or greater, then using poison would prevent the meat from being safe to eat. It doesn’t matter if the poison is capsaicin poison or poison dart frogs, the same rules apply.
So you can’t exactly use a blowgun to hunt a larger animal for food without severe risk to yourself and anyone else who might eat it, or anything else that might eat it.
Either way, if I can walk into a store and buy all the components to assemble a blowgun (which is legal in almost every state) then why is it only illegal o have the blowgun and not the parts in some areas? They haven’t done anything to actually control them or their construction, all they have done is make it so people can’t buy an assembled one.