Endwar 2024 has 2 special ammo tanks. One needs Demolisher Rockets and one needs Mega XL. This acts as a solution to both with mid performance.
You'll need a knockout, and two 20mm M3 screws. I don't have pictures of the assembly process, but just disassemble the knockout, then toss the colored frame + the mechanism that opens the breach. The custom barrel slides right over the existing plunger. It's really simple.
The author remixed this model.
I just stole the attachment point