Targut: Let me break down the MOS code thingy...
In 11B40, the 40 is referring to the skill level, as in rank. 10 is E-1 to E-4, 20 is E-5, 30 is E-6, 40 is E-7. The B4 he is referring to would be an SQI=Special Qualification Identifier. I had something similar in my old MOS, my SQI was F the F standing for flight status.
mrblech, you were an E-5, hurt your knee, and got discharged as an E-1? I have never heard of that happening, and I been around a while. If you got discharged as an E-1, it was for something else. Maybe you got busted for impersonating a sniper?
If anyone is actually interested in all that crap, the regulation governing SQIs is DA PAM 611-21. I just happened to know it off-hand, but if you dig you can probably find it.