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If it is not going into full battery then this certainly would cause light primer strikes resulting in a click instead of a bang. Assuming you are not using a neck only die then I would check the die set up. The shell holder should bottom out on the resizing die. If the die is set up correctly and you continue to have this problem then I would try to borrow a die from someone that does not have this issue and resize a few with it. You could have either an undersize die or a tolerance stack up issue with two mating parts being on the opposite end of the allowable tolerance.

I have fired unknown thousands of my reloads and have experienced only one (1) situation where a bad primer failed to fire. The odds of you having 3 out of 200 seem very remote to me.
I do not know much about "AR's" but the fact that you cannot eject the round sounds strange to me. I would really like to know if there was a dent in the primer after going "click". All this sounds like a mechanical issue to me but since I am "AR" ignorant I cannot offer any suggestions for mechanical situations.