Final answer:
Having a gun with its serial number filed off is illegal under federal law in the U.S., and there's no legal way to make such a gun legal again. Responsible gun ownership, including buying from reputable sources and observing local and federal laws, is advisable.
Step-by-step explanation:
It's important to understand that having a firearm with the serial number filed off is illegal under federal law in the United States. This regulation is part of federal gun control laws that began to be introduced in the 1930s, largely in response to organized crime. These laws became stricter following the turbulence of the 1960s and the assassination attempt on President Ronald Reagan in the early 1980s.
With that said, there is no legal way to make a gun with a filed-off serial number legal again. If someone is found in possession of such a firearm, they could be subject to criminal prosecution. Instead, responsible gun ownership, which includes buying from reputable sources and keeping guns secure, is encouraged. Check with local and federal laws to understand your responsibilities and rights when it comes to gun ownership.
Learn more about gun control laws