What is the average time it takes for someone to promote to E5 (Sgt)? What if someone was really determined? Could they do it in, say, 2-3 years? For scout snipers (MOS 8541), are they always a part of an MEU? Can officers hold that MOS? (scout sniper) What if you're a scout sniper as a corporal, then promote to sergeant, can you still keep your MOS? Or do you have to assume your NCO command of a platoon?