Milieu: Axis Universe
The KMZ99 Special Attack Craft is a Latavi weapon of desperation, used in Kamikaze style attacks on larger enemy space craft. Made from the components EK-101 Light Fighter, this craft was used during the attempted invasion of the Latavi worlds by the Grand Galactic Empire's rimward expeditionary fleet in 2256. The original concept was for the craft to launch the warhead, but urgency and desperation resulted in the creation of a suicide craft. The heroic volunteers that piloted them are credited with driving the Empires forces off and saving the Latavi from enslavement. KMZ99s can still be found in warehouses and underground storage bunkers as emergency reserve stocks. Some have even been removed from military inventory and sold off for conversion into sport flyers( minus the gun and warhead of course). The KMZ99 was armed with a single pulse laser cannon, and was fitted with a large anti-starship warhead.
I guess the size of the bomb also depends on how big of ships they were meant to take out.