So, what did the shooter use? Cnn says a 7.66 SKS(yes, 7.66) and Fox says an AK-47 with SkS ammo, then says he used an SKS.
This is the result when the uninformed reporting on that which they are ignorant of.
I've heard SKS from a number of sources. The SKS uses the same caliber cartridge as the AK and it's variants.
BTW, this ignorance shows best when it's applied to otherwise common knowledge, but it's present in nearly EVERY media story you read.