It's pretty clear that the Liberator in that particular test was not printed properly - the image at http://3dprint.com/wp-content/upload...er-picture.jpg shows a great deal of porosity in the barrel, so it's of no surprise that it failed. Additionally, the video noted that the .380ACP ammunition that the Liberator is designed to use is not available in the UK, which indicates that they probably used the much higher pressure 9mm round.

I and another engineer did our own test of the Liberator shortly after the design was released last year - details are here: http://haveblue.org/?p=1631