Gunslinger versus Beholder

[Shieldage]

I'm curious about how these iconic beasts handle themselves against D&D/Pathfinder-style firearms. Care to examine their stats, maybe throw up a short run through? Much appreciated.

Inspired by most recent chapter of DireSquirrel's 'Every Silver Lining Has It's Cloud' (http://www.tthfanfic.org/Story-17297-28/DireSquirrel+Every+Silver+Lining+has+its+Cloud.htm )

[Psyren]

The Gunslinger's main advantage is that the antimagic cone won't affect her (though it might affect her gun if it is magical.) Unfortunately, their weak will save can really mess them up if hit with the charm, fear, sleep or slow rays. The Beholder can also disintegrate her gun.

The right items will be necessary to take on a Beholder, but I'm not sure what those would be.