I spent 21 years in the US Army. Most of that time was in a light infantry battalion.  There are just over 500 members with only three sniper slots. There may be more sniper qualified personnel, but only three perform the job. There are over 400 personnel with 11-series MOSes (jobs) including 38 mortarmen. You'll notice, I gave Mazi a few options. Your character could be sniper qualified,  but serving in a different capacity. In fact the sniper experience helps increase the accuracy of the shooter.