Here’s a video from YouTube channel colinfurze, which details the creation of an “Airsoft Machine Gun Briefcase” inspired by the one in the Kingsman movie. Of course, I’m sure many of you are aware of H&K’s MP5k Operational Briefcase, which is the real world basis for the briefcase gun in the aforementioned movie.
You can check out more of colinfurze’s videos via their YouTube channel: https://www.youtube.com/channel/UCp68_FLety0O-n9QU6phsgw