A mech sized gyrojet would basically just be a rocket launcher or similar to the rocket assisted artillery rounds.. just scaling up the type of warhead that the bolters use then..Well, "Shinji and Warhammer 40K" and any universes based on the "Adeptus Evangelion" RPG have mecha-sized Bolters. Would be a manner of either adapting them for Gundam use or modifying the action so it can be mounted on a different frame... or resizing as needs be.
And Bolt rounds are gyrojets that actually work and even better than real life, so there is also that (figuring out how to make them work on a Mecha-sized scale from basic reverse engineering).
How about also the Gundam Firewall? Designed purely for firefighting work. Think this Gundam PSA but up to eleven.
An Eleven fire fighting gundam? ok. Would you say that one in the pic is a 79 or other model? (Or I can just take one of the models I got now and throw together a few ideas).. yeah.. Ok, I'll throw together a few fire fighting models based on one of the Gundams I've already produced and see if I can't crank it up to 11.