Footage dating back as early as 2012 shows 3rd Infantry Division indirect fire Infantryman, also referred to as 'Chucks', hanging some rounds during a training exercise.
For those of you unfamiliar with Chucks, they are a regular 11 series (11A, 11B, 11C) infantryman that go through the 14 weeks of One Station Unit Training (OSUT) on Sand Hill in Fort Benning Georgia. How do you join the army as a Chuck you may ask? Well, you would first have to receive a contract for an 11X role. From there, you ship to OSUT, complete OSUT, where your name then goes into Uncle Sam's hat.
Without continuing this mystery, moral of the story is no-one chooses to be a Chuck, It's simply needs of the army. When I say you get thrown into Uncle Sam's hat, it's a 50-50 shot whether you become an 11B (Regular Infantryman) or an 11C (Indirect Fire Infantryman/Mortarman). Both roles entail the same training, except 11C go into more detailed usage of their mortar equipment.
Now for you active-duty guys (Not sure how reserves or National Guard work), there are opportunities when you get to the line to make a transition between the two variants without it being a big hassle. If your dream is to become a mortarman, volunteer for it.