I fully understand the loyalty people feel to BP firearms but PLEASE PLEASE PLEASE bear in mind that transporting ANY BP or BP subsitute OR percussion caps on commercial aircraft is ALWAYS not only highly illegal and liable to put you in jail for a very long time and facing an immense fine but it also endangers the entire aircraft, everyone aboard it anyone on the ground it fall on top of.
If your in doubt as to transport restrictions, just take a look at the container. If it's classified as explosive of any kind, it's highly illegal to transport and even if it says flammable it can only be transported under certain restrictions such as loaded into cartridge cases that are packed so that they're kept separated from each other.
In the case of US citizens who try to take BP or BP substitute onto a commercial passenger aircraft, they're in breach of at least:
Air Navigation Order (Carriage of Dangerous Goods) Act
DOT Research & special Programs Administration
Patriot Act
Safe Explosives Act
Aviation & Transportation Security Act
TSA Security Regulations
AND several Executive Orders
On top of that is the possibility that several anti terrorism acts could probably also be applied should they feel the need.
Also remember there's no need to bring these items as similar items such as Sannadex are readily available here anyway.
Remember, they don't take any prisoners in this post 9/11 society in which we live.