A faulty 3D printed gun – who’s responsible?

3D printing safety issues exposed on TV’s The Good Wife

The Maze, Safety Pin, Design icons

A man downloads the design for a plastic pistol from the internet. He then uses his 3D printer to make a gun from the design specifications. When he takes it to the indoor shooting range, the pistol misfires sending shrapnel that cripples the man in the next stall.

Who’s responsible?

  • Carsten Pope – the man who printed the gun? (The ‘prosumer’*)
  • Chris Fife – the gun’s designer who posted the design specifications online?
  • Or somebody else – The 3D printer supplier? The supplier of the plastic filament?

A recently aired episode of The Good Wife dramatises this great story, full of twists and turns . . . And it all feeds into the questions surrounding 3D printing and consumer product safety.

*Prosumer is a term that combines consumer and producer (as described in my blog article 3D Printing and Product Safety)

Exploring the issues in court

The Good Wife is one of my favourite TV shows and it recently ran this scenario as its legal case of the day. Law firm Florrick, Agos & Lockhart led the case on behalf of the injured man.

A lot of the show’s focus was on the impact 3D printing can have on firearm supply. But many of the issues equally apply to general consumer product safety.

The Designer v The Prosumer

Initially the case was run against the gun’s designer.

The first ballistics expert witness said the gun misfire was foreseeable by someone with experience in printing and testing 3D printed guns. However, the expert said that Mr Pope had neither printed nor shot a 3D printed gun before. The responsibility then pointed to the gun’s designer.

The defence lawyer accused Florrick, Agos & Lockhart of not suing the prosumer simply because he had no money. She then examined the witness about ‘building’ versus ‘printing’ the gun, in the context of who manufactured the gun.

Learner designer and prosumer image

Modifying the design

A second ballistics expert witness came in to explain how easy it is to modify a downloaded design file, especially as the design was available as ‘open source’. She gave the example of making the gun handle smaller to better fit the user.

The witness testified that Mr Pope modified the design by shortening the gun barrel (and that this could have affected the way the gun fired). She added that designs available as open source could be easily ‘tweaked’ according to a user’s preference. The defence lawyer then asked if the original designer could have prevented any modifications being made to the design. The expert witness said No.

Raw materials and the printer mechanism

Outside the courtroom, the experts discussed how the quality of the plastics used to feed into the printer can impact the quality of the finished product, as does the infill setting.

Some tests were then done on the gun in question. The ballistics expert used Mr Pope’s 3D printer to make the same (tweaked) gun, but noticed a potential flaw in the print process. He observed some stuttering in the printer mechanism leading the plastic filament to feed unevenly.

This resulted in some print layers being skipped, which made the gun barrel weak and unable to contain the force of being fired. Perhaps the printer was at fault . . .

The printer manufacturer was then joined to the lawsuit. But this did not absolve the designer. His design specs had recommended the specific brand and model 3D printer used by Mr Pope, so that still potentially meant designer liability.

Tests would need to be run on a different printer (same brand and model), using the same design and tweak. The other 3D printer managed to produce a working pistol using the same design spec. This seemed to absolve the printer itself. The plot continued to thicken!

Kalinda to the rescue!

The law firm’s ace investigator Kalinda uncovered the idea that low or fluctuating temperatures can impede the 3D printed layers of the gun from adhering correctly. In court Chris Fife was challenged that he knew that cold temperatures warps the plastic and weaken the gun’s structure. And no warning was provided with the design. Mr Fife believed it was a case of ‘buyer beware’.

He lost the case on the basis of failure to provide clear instructions or warnings on a known risk.

In the end, the Good Wife episode left more questions than answers. They never really got to the bottom of why the gun failed. But it did highlight many of the possible pitfalls in the new 3D printing world.

3D printing and consumer product safety

If we set aside gun control aspects of the Good Wife episode, we see that many of the same issues apply to the safety of general consumer goods made by entry-level 3D printers. These issues include:

  • New designers and other new entrants into production and supply may not be cognisant of safety design principles or other ways to mitigate product hazards (e.g. warnings, instructions); and they may not be aware of standards or regulations
  • Customising may create new hazards (or re-create old ones that had been fixed by designers, standards and regulations)
  • Designers, home users and small producers may design variations to existing products without understanding the safety factors built into the original design
  • Due to the layered additive process, products may have limited strength, lower resistance to heat and moisture, and compromised colour stability
  • Consistent, repeatable production quality may be difficult to achieve with some materials due to heat stresses in the printing process
  • Pop-up factories and suppliers may become prevalent in the market, with some rogue operators among them
  • The quality of raw materials may not be subject to checks

These points are among those listed in my White Paper ‘3D Printing and Consumer Product Safety’, published in January 2015.

There’s no doubt some thorny issues and challenges arise with the growing popularity of 3D printing. You can download the white paper at no cost and find other resources on the topic on this website.


The Good Wife, Season 6, Episode 15, entitled ‘Open Source’, first aired 15 March 2015.