Can my college affect my grades and take away credit hours because I can’t attend class due to drill?

If you are not excused from the activity or class by the professor, then yes they can. Drill counts as a job and schools don't give a damn about jobs. You need to speak to the professor about finding something else you can do in order to make up missing the concerts or you need to speak to your unit about perhaps being excused from drill for the days that you need to be doing school activities.

I think you are confusing Grade Point with Credits Earned. If you miss a significant amount of class (no matter the subject) your grade is going to be affected. Basically, a 1.0 grade point is a D, which is still a passing grade, however, as a music major a D may mean you have to take that course over again since you probably need a C (2.0) for profession in your degree program. With a grade of D (1.0) you still receive your full credits (presumably the class is with 3 semester units) toward your total credits, but will not count toward your degree (often these are called "pass through credits, meaning you have the credits for the class but does not fulfil your Major requirement).

I would advise that you talk to your academic advisor as well as you degree program director and chair of the music department.

This is purely a thought, please understand that, I have zero clue if it'd do any good, however, I just thought it might potentiallynhave some value. I'm assuming you'd have already spoken with your advisrpor, possibly also the department chair. That being said, sometimes this might do some good, it depends on how involved the staff there might be, and how far they'd be willing to go try to help, obviously. You could always possibly go to the veteran advisor for the school, and document your drills, asking for their intervention, so far as possible. There's also the group I've read of, dealing with employers supporting the guard and reserve, though I can't recall the name at the moment. You could also ask your superiors in your unit for a letter to the school, asking for an incomplete, for a chance to make up the coursework involved, though I have no idea whether such a letter could be allowed. You might also ask the educational director for your unit, assuming there is one, if they could ask for help to your own unit managers, to see if they might possibly be able to intervene as well. You could also petition for a reasonable accommodation to the dean above your chair, then to whichever orivist at your school is above your chair and/or dean, as well as to the office of the president of your school. Now, having said all that, you need to know, explicitly, from the registrar whefer you go for the program, what are the precise, exact rules regarding such uncompleted. Can they be done retroactively at all? How long might you be allowed to have to finish e coursework involved? Would the faculty member for the course agree? Could be directed to accede, given that you were actually drilling? When would such forms for an incomplete need to signed by, and when would they need to he filed? If you'd need to repeat, could you ask for a retroactive withdrawal to allow you to redo the course involved? If so, given as you assumedly paid for the course once, could you possibly be waived to re-pay once again to do it a second time provided you tried to repeat it the next time it was offered? Could you possibly do it through and/or in supplement to other coursework? Mind you, and please understand, those are purely suggestions, of course. You might also possibly appeal to the school board of trustees, if at all alowabpe, or possibly to the faculty senate, most typical higher ed institutions generally have such bodies. Further, if any of the faculty might possibly be current or former military, ey might also possibly be sympathetic as well, if you asked. Obviously, all that would depend on your GPA, how far along you are in your program, the opinion of your faculty, advisor, and chair, as well as the caliber of your drill performance for your unit. However, having said all that, if you at least were to try such possibilities, assuming the drill was merely a hardship that temporarily interfered with your coursework, I think you might well at least conceivably have a halfway decent chance, if you handled such appeals correctly. You might also possibly ask if your unit superiors could go higher up to get you support, possibly seeking help from those above them, though your performance in your unit would clearly have to justify such support of course, which, obviously, is assumedly the case. I merely found your problem of interest, having gone through, over many years of undergrad and grad school, albeit quite some time ago, many similar problems, at various times, or seeing other friends of mine in similar circumstances. If be most eager to know your thoughts, if you might possibly care to elaborate at all; if I can offer any other possible advice, so far as possible, I'd of course most gladly try, so far as possible, by all means, as I am obviously most sympathetic, having quite frequently encountered such circumstances in Tue past, as I'd said, hope was of at least some potential use, many thanks.