The Spartan Laser is the most wildly inconsistent weapon in Halo 5. Which is surprising, because the weapon balance is really fantastic for the most part. But I've seen a lot of clips showing just how bad it is. Sometimes it can't even kill a mongoose and in the Youtube Link below, I posted a video where the Laser didn't even kill a Spartan with a direct hit!
The Spartan Laser desperately needs a fix in the next update. 343i can we please fix the Spartan Laser? It's really not worth grabbing in game if the hit detection and magnetism is so screwy that players can't even kill spartans with a direct hit!