“It’s Not a Crime, It’s Legal Here!”
This gets very confusing. A good example is marijuana. In many states, it is perfectly legal. But under federal law, it is still 100% illegal.
What does this mean? It means the "federal" government (think FBI, DEA) can still charge you with a crime, even if the state says it's okay. This is rare, but it happens.
This is also true for gun laws. A state might have very relaxed gun laws. But there are still federal laws about who can own a gun (like a prior felon) or where you can take it (like an airport). If you are charged with a federal crime, you are in a different world. The rules are different, the prosecutors are different, and the sentences are often much, much tougher.
You must have a lawyer who is licensed in federal court and has experience there. It is not a place for a beginner.