Give a zone this script:
;Artificial Intelligence Script
;Header
desc = Plr In Zone
;Triggers
:state=0,plrwithinzone=1:globalvar=70,setvar=10
Then give all of your guns this script:
;Artificial Intelligence Script
;Header
desc = Pickup Item (Deletable) [MUST USE PHYSICS ALWAYS ON]
;Triggers
:state=0:hudreset,hudx=50,hudy=90,hudimagefine=gamecore\text\pickedupanitem.tga,hudname=itemprompt,hudhide=1,hudmake=display,state=10,coloff
:state=10,plrdistwithin=40:state=1,playertake,plrsound=$0,hudshow=itemprompt,hudfadeout=itemprompt
:state=1:globalvar=70
:state=1,verequal=10:plrsound=$1,playerdrop,destroy
Make the guns always active. that should be it. when the player steps into the zone, he should drop all of his guns.