It seems like the news has become dominated lately by reports of tragic school shootings and other acts of senseless gun violence. As a result, lawmakers are trying to pass tougher gun regulations to try and prevent further tragedies from occurring. This of course gets gun rights supporters up in arms. In their attempts to defy lawmakers or to cash in on fears of a government crack down on personal firearms, some are turning to 3D printing as a means to produce firearms parts or even entire firearms that cannot be traced.

This interest in 3D printed firearms, combined with the growing affordability of desktop 3D printers, has led people to imagine a frightful future where people of questionable character sit at home and manufacture weapons without restraint. But their fears of untraceable and undetectable firearms filling the streets are founded more in media hype than reality.

I’ve been shooting for 11 years and have fired nearly every type of gun around, but I would never chance firing a gun made using a desktop 3D printer. The reason lies in the materials. While it is possible to create many components of a firearm using plastic and composite material, key components are generally made with 41xx class steel. When a gun is fired the expanding gases from the burnt propellant exert tens of thousands of pounds of pressure on the barrel, while the friction of the round leaving the gun creates temperatures close to 2,000°F. The ABS plastic used in desktop 3D printers can only withstand pressures up to 700 psi and becomes amorphous at 221°F.

It’s for this reason that it is no surprise to me that the .380 caliber “Liberator” 3D printed pistol from Defense Distributed, failed catastrophically after just one shot. A .380 round, which is smaller and weaker than a standard 9 mm round, has a maximum chamber pressure of 21,500 psi, well beyond what even the strongest ABS material can handle. With that difference in pressure, what is supposed to be a firearm suddenly turns into a grenade, threatening potentially lethal injury to both target and operator.

But pressure is not the only thing that would betray a 3D printed firearm. For any firearm to be useful, it must be able to hit its target. To improve a firearm’s accuracy, spiraling grooves are carved inside the barrel in a process called rifling. These grooves cause the bullet to spin as it travels down the barrel and it’s this spin that stabilizes the bullet in flight and allows it to travel straighter over a longer distance. In a .380, these grooves are worn away after 30,000 to 40,000 rounds and the barrel must be replaced or repaired. In a firearm made of ABS, these grooves would be worn away or deformed after one shot and further use would lead to deformation of the barrel itself, which could cause another catastrophic failure.

There are 3D printing technologies that use materials suitable for firearms production. 3D printing techniques such as direct metal laser sintering produce metal parts that are designed to withstand extreme temperatures and pressures and could be used to produce functional firearms. Problem is that these systems are designed more for industry than personal use and have costs that go into the six-figure range, so it’s not likely that anyone will be installing one in their home.

Michael Jermann
MJermann@wtwhmedia.com