Sorry for being away so long but pressing matters like having fun shooting for a week were in the way.
A buddy of mine and yours truly went via Delta Airlines from Ft Lauderdale to R/D to attend an IDPA match. Checking the gun in at Ft Lauderdale was absolutely painless. The gentleman at the counter was polite and professional which made the process a joy. A TSA agent was called to the counter, checked my guns and took the bag away himself.
The only nasty part was that my luggage was over the limit by 9 pounds and I was charged $80! Incidentally 300 rounds of 9mm ammo weigh 9 pounds and that made it the most expensive reloads I ever made.
Raleigh/Durham on the way back was about the same in professionalism & courtesy although the counter personnel were overwhelmed by passengers. No TSA agent came to check the luggage but the conveyor belt fed directly to the TSA X-ray machine placed about 20 feet away inside the secure area. Delta at R/D has a scale you can use right before the counters so I checked my luggage weight again. I had shifted a bunch of stuff from my bag to my carry on and I thought with no ammo other than my 3 mags worth of defensive BBs I was OK... nope, I was over by 4 pounds (I guess the goodie bag and other items picked up at the match were enough to screw me again) so 2 towels, and old t-shirt and shorts ended up in a waste basket. I checked in one pound under the limit
Note: If you suspect you are going to be over the limit with your luggage, take a spare duffel bag with you and split the load. You will be charged $25 for the extra bag instead of the $80 for overloading the plane. Does it make sense? Nope.