There are very few lawyers on this site and even fewer prosecutors. Any opinion you get will be worth exactly what you pay for it and you will probably get a few that disagree with each other.

If the magazines are legal in another state, and they happen to find their way into that other state, then what happens with those magazines would be governed by the laws of that state and/or local jurisdiction. Colorado law would have little if any effect on transactions conducted in another state.

I do not believe there are any Colorado LE conducting sting operations inside other states, attempting to identify and arrest Colorado residents who happen to break the current magazine law.

Always take anything you read on the internet with a healthy dose of cynicism.

Be safe.