I think eventually 3D printing will come to be a commonplace manufacturing technique. Companies will be able to make custom metal parts for each individual customer. And not just for the gun industry. It's rather short sighted to outlaw all 3D printing processes before they even have a chance to make it in the marketplace.
Just gun parts, nothing else. I just think it's an infringement upon our second amendment rights to make it illegal. I hope that someone in Philadelphia challenges the law.