Made of two pieces of pipe that fit snugly together, the 'paliuntod' were simple, single shot guns. The 'paliuntod' is a type of improvised shotgun commonly used by guerrillas and the joint American and Filipino soldiers who remained behind after Douglas MacArthur's withdrawal. Pipe guns were first seen in the Philippines during World War II. They require registration under the National Firearms Act and a tax in the amount of $200 to manufacture or $5 to transfer is levied. In the United States, pen guns that can fire bullet or shot cartridges and do not require a reconfiguration to fire (e.g., folding to the shape of a pistol) are federally regulated as an Any Other Weapon ( Title II). Some pen guns are not designed to fire regular cartridges, but rather blank cartridges, signal flares or tear gas cartridges. Early examples of pen guns were pinfired, but modern designs are rim or centerfire.

They generally are of small caliber (e.g. Pen guns are zip gun-like firearms that resemble ink pens. Homemade pen guns (Museum of the History of Donetsk militsiya). Larger zip guns, such as homemade shotguns called tumbera (Argentina), bakakuk (Malaysia), or sumpak (Philippines) are also made of improvised materials like nails, steel pipes, wooden pieces, bits of string, etc. The better designs use heavier pipes and spring loaded trigger mechanisms.

Such weak tubing results in a firearm that can be as dangerous to the shooter as the target the poorly fitting smoothbore barrel provides little accuracy and is liable to burst upon firing. A rubber band powers the firing pin, which the shooter pulls back and releases to fire. 22 caliber rimfire cartridges, even very thin-walled tubing works as a barrel, strapped to a block of wood for a handle.

For small, low-pressure cartridges, like the common. Zip guns are generally crude homemade firearms consisting of a barrel, breechblock and a firing mechanism.

Fallout 4 nail gun