Normally, if its important, irreplaceable or dangerous, is probably not a good idea to steal it.
Raiding the armoury would be, along with distracting for security, unfair for both security for having less weaponry to defend themselves with and for antags for having to deal with a non security member armed with a laser gun when they are not supposed to have that in any ways.
Maybe you should try finding fun in other stuff that is not breaking the law, like chilling with friends, building and such.