Board Thread:FAQs/@comment-26395021-20150519000208/@comment-4820209-20150519050839

That's like asking a sledgehammer to go against MJOLNIR. A Gravity Hammer has the ability to literally manipulate gravity. (Allowing for a "push and pull" feature) It can deflect incoming objects.

You can use all the amplified force you want with Magnhild, and the Gravity Hammer user can simply push it away, or deflect it, screwing over your attacks until you run out of ammo (Grenades to amplify force), or grow too tired to swing anymore.

A Gravity Hammer alone can kill a Spartan-II; essentially the best of the best, with one hit, and it can outright kill a human with a glancing blow (An ODST in Landfall, and a NMPD Officer in Halo 3: ODST suffered this fate), meaning that Nora (rightfully assuming she's the one in control) would most likely be outright incapacitated or killed from it.

Tl; dr? Gravity Hammer. All the way.