Guns and Firearms: How dangerous are modern air rifles?
It depends on the projectile and pressure. Most modern airguns are small-caliber and moderate velocity, similar in performance to a .22 Long Rifle in power- a 5.5mm, 3gr conical lead bullet travelling approximately 400m/sec. Lethal, potentially, but not tremendously damaging without hitting something vital.However, there are larger caliber airguns that fire heavier projectiles. The famous Austrian Windbusche repeater was 13mm, or .51 caliber. Modern hunting-type airguns are available in a plethora of calibers, and while not as popular as cartridge firearms, still quite viable as hunting rifles under appropriate circumstances- they were extremely popular at the turn of the century for poachers due to a relatively quiet discharge, and are frequently used for pest and small game hunting worldwide, and models in larger calibers can be used to take deer and boar quite effectively.However, mechanically, the pneumatic rifle holds two distinct disadvantages to a cartridge firearm- they're relatively limited in terms of power due to the speed and pressure at which compressed gas can be discharged, and they're mechanically complex compared to a cartridge firearm, with more wear-prone components such as seals and valves.Basically, the advent of cartridge firearms using smokeless powder simply evolved the platform to be more robust and powerful than the airgun by a wide enough margin there's been little interest in them since.
Is is true that you can legally make your own weapons? Does this extend to high quality mimics of actual firearms using 3D printers or custom hand designs? Would making a firearm this way allow you to legally make it fully automatic?
Within the United States, it is generally legal to make any firearm you could purchase. While laws by state vary, on the basic federal level you can manufacture anything you like without a permit as long as you don't violate the National Firearms Act. In essence, this means you must file and get approved lengthy legal paperwork for any of the following: silencers, fully automatic and burst fire weapons, destructive devices, short barreled shotguns and rifles, miscellaneous "Any Other Weapons".On the other hand, you can build any of the following without any paperwork whatsoever: rifles, pistols, revolvers, shotguns, black powder weapons.The quality and method by which you produce a firearm is not regulated as of yet.