I am the owner of a machine shop that produces special parts for scientific and laboratory instruments. I often travel through the Phoenix and L.A. area airports carring sample metal parts in my briefcase. It is extremely unusual for security to question what I am carrying, and when they do (maybe 1 time in 50) I am able to satisfy them by just showing them my business card.

I would think that it would be easy for several people to dissasemble a weapon, carry it through "security" and reassemble it.

Obviously airport security is effective at keeping out the crazies, and the inept, but would be only an inconvinience for the dedicated and knowledgeable terrorist.