Last Fall a group of us flew to sask Canada for a bear hunt. I had my 300 win mag and my bow.

From what I got off the tsa web page and how it worked for me ( its diffrent in diffrent airports )

1) have your firearm in a hard case/ locked , broke down and unloaded, you may have ammo in your gun case.
2) when you check in your luggage they will ask you to unlock and open your gun case, inspect to make sure you are unloaded ( I had my bolt out and my mag out )
3) they will place a signed doc that you showed them it was unloaded in your case.
4) ( this is where it depends on the airport ) I was ******ed to TSA by an airline employee,
5) TSA first x rayed the case, then asked me to open it, they hand inspected it and then closed it and required that I lock it.
6) airline employee and I walked back to check in and they checked the gun case with my other luggage.

On our return trip at step 4) we went to TSA, they x rayed, hand inspected, requested I lock it, and from there it went on a belt and into secured luggage area. it did not go back to the baggage check in counter.

the tsa website has all the info you will need on taking a rifle with you. If your going out of the country, make sure you get copies of the paper work you will need, prior to going. You'll want to fill everything out but don't sign it, untill you are in customs.