Around the world, governments attempt to limit subjects' legal access to weapons—ostensibly to keep the peace, but in reality often done to minimize challenges to government power. And, around the world, those subjects defy such restrictions, often going so far as to manufacture weapons outside official channels. In fact, DIY firearms ranging in sophistication from muskets to grenade launchers exist in the millions across the planet, according to a new report that should (but won't) finally demonstrate to government officials the futility of efforts to disarm people who insist on being free.

I've written before that defiance of restrictive gun laws is far more common than compliance with them, and not just in the United States but in countries as far apart as Australia and Pakistan. People refuse to register their firearms, they modify them, they smuggle them, and they make them at home and in illegal workshops.

That last approach is the subject of Beyond State Control: Improvised and Craft-produced Small Arms and Light Weapons, a report published this month by the Geneva, Switzerland-based Small Arms Survey. "Improvised and craft-produced small arms and light weapons are widespread in many parts of the world," authors N. R. Jenzen-Jones and G. Hays write. "More data is needed before researchers can arrive at a reliable estimate of these holdings, yet the figure is doubtless in the millions."

The types of weapons people produce for their own use range widely in sophistication: "from crude, improvised single-shot guns to semi-professionally manufactured copies of conventional firearms." The trend is toward more advanced weapons—including mortars, recoilless weapons, and grenade launchers—to satisfy the demands of non-state groups that are often locked in conflict with the governments attempting to disarm them.

That illicit production is so common shouldn't be a surprise. The authors point out that production techniques for firearms continue to be based on 19th-century technology. In an era when home-based hobbyists have access to equipment that would make industrial age entrepreneurs drool, that means there's little barrier to making what can't be legally purchased.

"Consequently," the report notes, "individuals with the desire to undertake fairly straightforward research and acquire basic tools and equipment can manufacture viable homemade small arms."

While many headlines have been devoted in recent years to 3D printing and CNC machinery, which ease the task of manufacturing goods including firearms, these high-tech approaches haven't been necessary to kneecap efforts by governments to disarm their subjects. They do, however, lower the barrier to entry for those who would make their own guns.

"3D manufacturing will not render current international and national controls on firearms obsolete," the report's authors say. "It may, however, make applying these controls more difficult, in effect posing new law enforcement challenges. As additive manufacturing technologies continue to improve and become more readily available to private individuals, it will become increasingly difficult to enforce regulations on firearms manufacturing."

A technology that is already making a major difference in easing DIY gun manufacturing is the internet. "The online sharing of expertise and instructional videos is facilitating the craft production of increasingly sophisticated weapons, including sub-machine guns and anti-materiel rifles," the authors write. But you don't need to take their word for it; instead, you should check out Reason's handy-dandy guide to making your own off-the-books handgun. Video instructions are included.

As of yet, DIY weapons probably constitute a small fraction of the firearms in circulation. Nobody knows how many homemade guns are out there for sure, of course, but commercially manufactured guns remain legally available in much of the world, and easily accessible through black market means in much of the rest. Buying what you want is generally easier than manufacturing the goods.

But where restrictions are tight and illlicit manufacturing has become well-established, DIY guns are increasingly prevalent:

Improvised and craft-produced small arms account for a sizable proportion of weapons seized in domestic law enforcement operations in several countries. In the UK, some 80 per cent of all guns used in crime in 2011 and 2012 were improvised, craft-produced, or converted; in São Paulo, Brazil, 48 per cent of the sub-machine guns recovered during the same period were homemade; and in Indonesia, 98 per cent of the guns confiscated from robbery suspects in 2013 were homemade.

Slightly savvier restrictionists realize that devices that can be manufactured in many people's garages are about as a likely a target for prohibition as plants that can be grown on windowsills. They've turned their attention to ammunition, which at least is consumed and must be replaced.

But reloading expended cartridge cases—DIY ammunition, in other words—is a popular pastime in the United States and elsewhere. "People typically reload to save money, craft a cartridge for a specific need, rather than worry about future government controls," a representative of Dillon Precision, an Arizona-based maker of reloading supplies told me. "But this is a secondary reason to reload, provided you store the components you can't fabricate or reuse."

Components can also be improvised, as Jenzen-Jones and Hays note:

The fired primers of centrefire cartridge cases are sometimes reused with match heads, small percussion caps from children's toys, or other impact-sensitive mixtures that can replace original priming compounds and provide reasonably reliable ignition sources. A propellant charge, whether loaded into a cartridge case or directly into a muzzle-loading firearm, can be improvised, while projectiles—especially shot—can easily be cast from lead or other metals.

While commercial ammunition remains available in vast quantities for most of the world, substitutes have been improvised when needed and the report includes photos of some creative examples.

"Regardless of how they are made," the authors conclude, "improvised and craft-produced weapons … will continue to pose global challenges to law enforcement and policy-makers." Some of us might say that, in a world inhabited by people who view the governments that would disarm them with well-earned distrust, that's exactly how it should be.