So I reckon it sucks that TR Soundwave does not come with his signature weapon. However, my housemate recently got a 3D printer so I figured I would try to give Soundwave his correct gun. I made it in tinkercad, its pretty simple since its my first 3D printed part, but it does have a semi compact mode for storage (can peg into his back like the rifle). It could be cleaned and painted better but I was in a hurry. Edit - Added pic of back storage mode
I'm working on a new version that will fully collapse and have better handle placement in battery mode. I does mean that the gun tip will be narrower than it currently is, but it should still look fine. Hopefully I will have it designed and printed in the next few days.
So I made some more progress with Soundwave's battery rifle. This is V4, V1 and V3 were both non-functional and V2 is posted above. In this version battery mode is improved. The tip fully collapses into the battery. The handle ends up in a better location for storage on Soundwave's back. The gun mode also looks better because I added more thickness to the barrel which made it print more accurately. I have set this design as public on tinkercad, its named "TR Leader Soundwave Rifle v4". I printed it with supports, but I'm not totally sure it needs them now that the barrel is thicker. It still needs a bit more paint work but I thought it was time to share my progress, I hope this helps others get Soundwave correctly kitted out.