He was on active duty for training earlier. When I say active duty, I mean assigned to an active unit in the field.
If you have more information on his active duty time, I would love the hear about it. I personally think he is nothing but a politician. He is no Chesty Puller or Audie Murphy. I just don't like it when people like him try to throw his military career up when he didn't have much of one. I really can't think of many politicians who had distinguished military careers.
One of his MOSs on active duty was as a DI at Parris Island and again, unless you've seen his entire OQR, which he should release, or his DD214 you're speculating as to how much time he spent on active duty and as an active reservist.