It's just the same international (ICAO) standards.
1. Airline approved locking rifle case. Either metal or heavy gauge plastic.
2. In the US, ammo can be shipped inside the rifle case. For international travel, the ammo MUST BE SHIPPED SEPARATELY from the the rifle case. Ammo case must be lockable and either wood or plastic and the ammo must be stored so that the rounds can not make contact with each other i.e. loose bulk pack. ICAO limits total weight of LOADED ammo to 5 kilos (11 lbs) and is NOT supposed to include the weight of the ammo case - subject to check-in agent interpretation.
3. The rifle case should be locked with NON-TSA openable key or combination padlocks. The rifle case is to ONLY be opened in your presence.
4. Ammo case must use TSA openable key or combo padlocks and the piece of checked luggage must have a TSA openable key or combo lock. You MUST declare to the check-in agent that you have ammo inside your checked luggage and what specific piece.
5. Depending on individual airline, or usually the airline check-in agents "interpretation", the ammo box CAN be put inside a regular checked baggage; However, this also seems to be subject to individual check-in agent interpretation.
Recent case in point. Last June's trip to Botswana. Per the Bots Air website, the locked ammo case COULD be inside the checked luggage. When we checked in, the agent in J'berg told us we had to take it out. On the return flt from Gabby back to J'berg and our Delta connecting flight, we both had the ammo boxes in our respective checked luggage and when we checked in for the flight, we declared as required and the ammo stayed in the checked bags. Go figure?! This same thing happens frequently so just be prepared either way and you'll be fine.
As far as rifle cases, the first couple of trips we made, I had a nice aluminum case. Lasted two trips. I've been using the same Pelican/Storm cases for the past 25+ trips. They are a little banged up but still more than serviceable. If the do get damaged, they've got a lifetime warranty. Same for the ammo cases - storm/pelican. Whatever you do, don't just try a cheap $30 Plano from Wal-Mart. You'll put a nice rifle on the plane and you could end up picking up a banana - no joke, saw it happen to a guy.
What we do is take the factory foam out. Put a layer of clothes in the bottom for padding. Then the rifles in zippered soft cases. The the top layer is a couple of heavy sweaters and medium weight coats. You can also put your knives, flashlights, spare scopes. GPS etc and any other kit inside up to the 23 kilo (50 lbs) weight.
The last thing I put in EVERY piece of checked luggage, rifle case and ammo box is a copy of my passport, airline ticket, 4457s, invitation letter and a copy of the temp import permit if I have it and a SPARE SET OF LOCKS with the same key or combo with a note attached asking that they be used IF the original locks were cut off for some reason. I have had locks cut off my rifle case ONCE for some reason transiting via Europe.
Binos and camera, computer always in our carry-on. DO NOT put a spare scope in your carry-on! It is considered a "firearm component" and is likely to be confiscated.
ALWAYS, print out each airline's baggage and firearm info from their website THE DAY YOU PURCHASE YOUR TICKETS and carry a copy with you. You can use it to maybe convince a check-in agent what the airlines rules are regarding firearms/ammo, BUT don't get into a urinary Olympics with them. Politely acquiesce or your stuff could end up in BF Egypt! And IF you have to pay any extra fees ALWAYS get it on your CC. Then when you get home, simply submit a copy of your ticket, baggage agreement and charge receipt and ask to have the charges taken off.
28yrs in the military, 68 countries and in the past 15 yrs 35+ trips to RSA, Namibia and Botswana.