I have flown into and out of MCI (KCI). No problem.
In fact, except for an annoyance with AirTran out of Miami, in fifteen years, I've never encountered any problem with any airport.
People flying with guns is ancient news, while of course, it's new to some people, so:
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Make sure you get and sign the red or occasionally, white tag to declare an unloaded firearm. The agent will ask you to place the signed form in the case your gun is secured in.
The "ammo issue" has been the only source of confusion on the part of TSA agents. So, I paid less than $10 for a security box from Office Depot.
It's a small (7in x 7in x 2in) metal box with a lock on it. There's room for two or three ammo boxes after discarding the plastic inserts it comes with. I place my ammo in a factory ammo box, like the one the ammo came in. Then, lock the ammo box in the security box. Since doing this, there has not been a single issue about ammo.
For the gun, I use a Center of Mass portable gun safe.
It has a cable one can use to secure the gun safe to another object.
http://www.center-of-mass.com/
My luggage has metal struts inside that house the collapsible extended handle. I wrapped the security cable around a strut inside the luggage. This adds a step to separating the gun from the luggage. Without cutting the cable, the gun and luggage stay together. TSA or I can open the safe while it's tethered to the luggage.
I wait near the counter, while my luggage is scanned, for a "thumbs up" from TSA before going to my gate.