All guns degrade after being fired, but modern production firearms are just plastic wrapped around metal tubes. 3D printed guns have always worked on the same principle but it takes time to develop them to the same safety standards.

Not if they're made correctly, with good materials like nylon-cf, correct print settings, and good post processing. It's a process that takes a day or two and requires a small amount knowledge and skill.

A handgun made like that will function for thousands of rounds.