Talk:Affinity/@comment-8982078-20130720070615/@comment-9349503-20130720074745

It doesn't. And it's easy to test. Run through a mission and use nothing but your Warframe powers to get a few kills (zero weapon kills). But specifically make sure to break chests for Affinity Orbs and pick up a few. At the end results screen, you'll notice your weapons got nothing at all XP-wise.