Hey Joerg, I had an idea for an air gun projectile and made one that would fit in a 15mm pvc barrel (I don't think that your laws would allow) I think that you would be creative enough to work something out that would work for you. You could make a tracer using a sparkler and your launcher could light it and have a magazine or something creative and cool like you always do. A photo of my tracer dart is attached except that mine has now got a sinker on the nail to stop it tumbling. The sparkler wire is flexible enough to simply bend around if a channel is cut for it. I would enjoy seeing your interpretation.
Tony ImageUploadedBySlingshot Forum1475567394.876980.jpg