used some old pen parts, a gundam bazooka, and some aluminum tubing pieces...seems to work pretty well.
There is something awesomely cool about small robots with big guns, I did something similar with my Cj a while ago
It's just some of this stuff HEXAGON MINIATURE TERRAIN 28MM SET (LARGE) by Pegasus | eBay UK I bought a job lot of it off of ebay a while ago, snapped it all together and it's stayed in the same form ever since. It's not great tbh.