Converting grenade launchers to storm bolters

[Skoby]

I'm starting an ad-mech force using the GK codex and I need some storm bolters for warrior acolytes, I was looking for storm bolter bits online when I spotted a bunch of grenade launchers and decided to buy a bunch meaning to convert them to represent a drum fed storm bolter that could be used 2handed using greenstuff and plasticard rods. Has anyone seen anything like this done? Main issue is the bits havent actually arrived so I've no idea if this could work so if anyones worked with these bits could tell me if it's feasible or if I'm wasting my time.

[Bat Manuel]

Just cut off the barrel and replace it with two side by side rods.

[Prometh]

If you are talking about IG grenade launchers i think its definitly doable, but you will probably have to use some greenstuff to make the typical bolter housing