9mm = Sept.
.22 semiautomatic = 11 + 11 = 2nd 911 = 22 Qabbalistic Key.
33 victims = 33 degrees of Freemasonry = 33rd degree Revolutionary grade.
Ismael Ax = Death to Ismaeli bloodlines.
Old Boy = Cho's rage against the Illuminati.
I got most (OK half) of that at the time, and it made naught sense. the 33 made the most sense.
Always amazed me that one of the most revered firearms in the U.S. was also designated 9-11