Talk:Affinity/@comment-26561328-20150701174113/@comment-8256051-20150701180128

They'd get exactly zero xp.

XP is split between the weapon that gives the killing blow and your warframe (killing with an ability gives 100% to your warframe). Objective XP, casting XP and allied XP is split between all your equipments.

If you kill everything with your primary : your secondary and melee will get absolutely no XP.