Bar storm is the best weapon in the support class, it has great hip fire, perfect for cqc and mid range, select semi auto and it becomes a sniper rifle. Only down fall is the small mag. It also has the fastest ttk for all the support guns.
But that small mag is a huge drawback, not great for suppressing fire compared to the other choices with much, much larger mags. The best weapon is the one that works best for you. For instance, I’ve got 121 Service Stars with the Selbstlader Marksman as a medic. It’s far from the most common and I don’t see it often in games but it out performs every other weapon I’ve used in that class. Others have different preferences.