You could try it, i seriously would not recommend it though. What I've posted may be more complex, but it is what has been proven to work.
Who knows, it may turn out great, but the way I look at it is: have you ever noticed how a regular gravity feed hopper (shake and bake) will stop feeding every few shots, and then has to be shaken? This is because you are feeding a large number of objects into a small hole (no matter what is done to reduce friction) well with the magazine you are spring compressing your balls, making your jams into large messes that you can't shake your way out of, then you pull the magazine out of the marker to fix the problem and BAM all the balls inside are ejected every which way. This is just what I for see, but I would love to see you prove me wrong.
Are you planning on having multiple magazines? how do you propose keeping the balls in the magazines while not in the marker? Just another issue you're going to have to look at before it is all said and done.