My stuttering actually reduced very significantly while in military, I didnt have any blocks. I think it is because of somekind new persona you create while being a soldier in addition of the authority and charisma you get (if you are on a leading role). I served as sergeant, and my tasks included a lot of speaking up to groups of 100 people, which was perfectly fine because I didnt stutter at all. After my service ended I felt the persona i had in the military, kinda stripping away from me, and noticed im starting to stutter again.