I clearly and very plainly stated in my post............ nobody NOT EVEN I can tell you what the rules will be at the time you check in or depart
The solution is quite simple. Your legally entitled to lock your bags. The catch is that you must be present to have them inspected.
With that bit of info the rest is very easy. You can pack your ammo the way the airline regulations suggest, or "allow" the airlines will not take your gun case in any airport in the USA...........It must go to the TSA agent for inspection.
When you tell the gate agent that you wish to lock your suitcase he/she will have that bag transferred to the TSA security section of your chosen airport as well. You cannot carry it to that TSA section, or return it to the counter which is how it's done in some airports. Other airports will have the baggage go to the aircraft right from the TSA security check point. If your using an airport that requires the baggage to go back to the gate the airline employee will have to transport it back for you. Once inspected you're no longer allowed to touch that bag. TSA will place a sticker seal across the openings or a Blue zip tie through the padlock holes to verify it's been checked.
This of course adds to the time you will spend in the airport as they must locate somebody who's not doing anything else to assit with the baggage now. OK.......once at the TSA inspection point they will ask you for your keys to open the guns and the luggage. Sometimes you get lucky and they don't open anything but just Xray the bags. Not typical it's usually a full hand inspection.
If a hunter drops his bags and walks away at this point he's a fool without any guidance by a professional to have helped him through the whole process for the big bucks he's spent on this trip! You do not leave that TSA inspection point until you have been cleared to do so, and your bags have been secured and your given the thumbs up that all is well.
Anyone who just drops their bags at TSA and walks away must be out of their minds to assume that all will be well as they head for the bar! While you're there at the TSA inspection point you can watch them go through your things and answer any questions they may have. If the question comes up about having the ammo placed in the gun case it's a simple matter to state that SAA suggests that ammo is placed with the guns. It's not a TSA rule, it's and airline regulation. They have two options, check your story, or let it go. Maybe a third option which has never happened to me yet.......they simply say sorry buddy no ammo with the guns. If that's the case and you have a bugger of a TSA agent, it's no big deal have him set the ammo into the other piece of luggage you have sitting right next to the gun case. It's also going to be inspected by him/her and locked as well.
I cannot say enough about the good effort, the help and friendly people I have dealt with in this business while transporting firearms around the USA and frequently international. I have never yet had a difficult or miserable TSA person to deal with. On the contrary I have had the majority ask about my guns, or my trip. Most will go out of their way to comfort you that the bags will make the flight and they usually are very careful about repacking the guns and luggage. I think the way you approach these folks and the way you speak with them goes a long way towards how your treated in return.
There have been several instances when a TSA agent has said to me, You cannot pack the ammo with the rifles. My reply was" is that a TSA rule or airline rule". In every case they did not know where they learned that statement from. In every case they asked another TSA agent who either said " yeah it's fine with XYZ airlines" ..........or "I don't know" then they make a phone call and yell over to the inspector......"yeah it's fine"
I fly almost every month with rather expensive archery gear. I shoot competitve and must travel often with the bow case. It is aluminum and looks like it would carry a gun. When the gate agents see this they always ask if it's a gun. I say no it's archery and they proceed to check it through. I hold it back and say I want to lock it so it must go to TSA. About 1/2 the time the agent will tell me it cannot be locked only guns get locked. I say nope, I want a hand inspection and this will be locked. They begin to argue and I simply as for a supervisor who gets it to the TSA for me and they inspect it and lock it for me. After these debates went on far too many times I bought a 25 dollar piece of crap derringer. It's in the bow case now, I've never even fired it! When I check in now there is a firearm in the bow case and that ends that struggle at the gate.
However when I get to the TSA for inspection, they never fail to ask what the heck is that little derringer for? I explain why I use it in the case and without exception they all say........ " your can lock any bag you want without the gun inside you just have to wait til it's inspected by hand to relock, then have it sealed up by us". Yeah I know but the debate at the ticket counter is a waste of everyones time and it was getting old for the frequency that I travel with archery or firearms.
There is a very diverse level of education and experience with the airlines and the TSA people. Firearms are not seen by them as frequently as ordinary luggage, nor do they get the request to lock plain luggage very often. The accepted rule is that all checked bags must be unlocked. That's 100% true............unless you request, and have the time to wait on a TSA inspection to have it done.
Follow the rules of the airline to start with
Proceed through the TSA inspection with a copy of the Airline regulation documents
Speak nice and polite to the TSA people ( they deserve it)
If there is a serious problem with the ammo in the luggage have them place it in your other bag.
It's not a big problem, just follow these easy steps and you should glide right through the process.
NEVER LEAVE THE TSA INSPECTION POINT UNTIL EVERYTHING IS CLEARED!!!
I'll say this in closing. If you choose an outfit to hunt with that has not helped you with this process every step of the way, I sure wish you well with the rest of the trip. When you're spending 5-10K or more on a trip like this you deserve a whole lot more then just having somebody take into the bush hunting and allow you to struggle the rest of the way on your own!
Any hunter/visitor travelling that far with guns to a foreign country for the first time should be given plenty of help to do this. At least in my opinion. We treat every visitor as if it were our own family doing this alone for the first time.