Assuming you are right that OBL actually participated in a fire fight (which I seriously doubt) short barrel, small caliber weapons do not lend them selves well to the terrain in Afghanistan. I am speaking from the viewpoint of an 11B40 combat vet, not a military theorist or gunsmith.
I never said he used that Krinkov, although in cities and towns, it's probably about as good as a shorty M-4.