Mirage Deadeye Ascension

Hello - got my 4th ascension and picked Mirage. Mirage Deadeye now shows in my skill tree but cannot activate it. Ran several maps and tried rolling to activate many times but nothing. Also running Boar as a companion. Any help greatly appreciated.

First of all, did you socket a ranged attack into Mirage Deadeye ? Second, to proc the effect, you need to use a projectile attack. And finally, did you look if this meta gem was activated in your spirit menu ?