I would also suggest allowing at least an extra half hour for inspection. On rifles I remove the bolt & handguns I lock open the slide & remove magazines.
I travel with mine the same way out of Dulles and Reagan. No problems from traveling with both for the last three years, but lessons learned:
1. Don't expect the TSA rep to know what to do, they train new people too. I've had to repeat several times at the counter that I am declaring the weapon in the case, but only on one trip. It took the full extra 30 minutes to get the inspection and securing completed.
2. Every airline has required the ammo to be in an ammo box, factory or commercial box did not matter, but it had to be in a container and secured. Blue's link above will give you ammo quantity limits.
3. The transport case is supposed to be "pry-proof", think Plano $30 flexible case that locks - bad, and a Pelican style with the hard shell-good. The better cases will be marked "TSA approved", as will the case locks. The case must be secured so that the locked lid can not be pried open up and the firearm extracted without opening the case.
4. Have the keys, if they cut a lock(s), you have to be able to replace it to continue your trip. I usually buy a four lock set, two go on the case, two go inside in case TSA cuts or loses one. In theory, once the inspection is done at the departure and the case is locked, it stays that way until you pick it up at the arrival airport.
JMO< East Coast airline terminals are less prepared for weapons transport than Western desitinations. Virginia is usually a bit more trying and time intensive than Denver or Idaho/Washington.
