I'm going to be sending my group's Kill-Team against some Necrons in the near future, and while looking over the stats for Canoptek Scarabs, I found something that I'm not quite sure how to apply.

Scarabs have the Ravenous ability, which is "Whenever a melee weapon that does not have the Power Field Quality hits a Horde of Canoptek Scarabs, there is a 25% chance the weapon is destroyed."

I like this ability, as it'll make the more melee orientated marines think twice about charging in or staying in melee. But those same characters are Librarians, and as such, armed with force weapons. As you guys may have guessed from the title, I do not know how the Ravenous ability will work regarding force weapons. From the force weapons entry in the core rulebook, all I can find that relates is 'Force weapons cannot be destroyed by a power weapon's field', not to mention that force weapons don't have the Power Field Quality.

I could see it going either way. RAW, the force weapon takes the chance of destruction, and I can justify it with the fluff that a Power Field is disruptive, and the force sword's psychic nature cancels that out, while scarabs are literally eating the weapon as it passes through (with the Power Field immunity to their ability being because no actual physical contact is made between the weapon and the scarabs, while a force weapon needs to connect and then channel psychic energy). But I have no idea what the RAI might be here.

So, what do you guys think?

I would say there is a chance of the blade being destroyed. This is because a force weapon in the hands of a non psyker is just a lump of metal with shiny bits on it. Only when wielded by a psyker, does the might of the wielder make use of the psycho-reactive material imbued within the weapon to enhance the power and give it extra bite and indeed as the rules even state

"Unless wielded by a psyker, force weapons simply count as a common Astartes sized weapon of the appropriate type".

Force weapons do not need to make contact though to start applying psychic potential as represented by the rule that they add their PR to damage/pen (Core DW Rulebook P155, middle paragraph). Afterwards though they can channel their energies further through the weapon into their victim.

It's very unlikely that a non-librarian would take hold of it but if it were me I'd say it cannot be destroyed and is considered as having a power field of sorts (enough to negate other power weapons destroying it or destroyed by effects which wreck normal items but not enough to do the same to any other) unless a non psyker tries to use it and then apply the 25% chance as it then defaults to just an inert sword.

Ask yourself this, if a power weapon can't break a force sword, why would a scarab be able to? (assuming its being used by a psyker at the time)

Thanks guys!

I really wasn't sure how the psyker 'charged' their force weapon in the default state, but rationalising it as a mini-power field makes sense.