After months I finally have something to show again.
Unfortunately I suck at arts and the following model took me 3 days to complete, whereas a professional artist would do that in 3 hours but include more detail (e.g. no screws at the grip, no "grip" at the grip).
Bumsrohr would translate to something like
bang / boom tube, so essentially you pull the trigger and then
bada-boom, however I am keeping that as pseudo trademark