2 | ship must have mil>0, glim>0, gun>0, shell>0, eff>=60
20 | at sector that doesn't exist
22 | at ship that doesn't exist
24 | at valid target, but no mil
40 || ship firing nowhere (shells consumed)
44 | at ship out of range
46 | at sub, server pretends out of range
51 || ship firing at bogus target
58 || ship firing at undefended target
59 | 100% bb with 1, 2, 3 guns
68 | likewise 1, 2 shell (take care to avoid automatic supply)
77 | likewise 1, 2, 3 mil
95 | at ship, fractional range, ~50% chance