Ackley questions, FPS drop, ammo into other countries etc.

So firstly, concerning a 338-06, it looks like you get about 50 fps more.
I know you get better brass life.

What is the FPS drop if you shoot say a 225 gr factory 338-06 cartridge in a 338-06 AI chamber ?? IE
it blows out the case so I assume there is some velocity loss.

Can you fly into say Africa with 338-06AI handloads with WB brass with the proper 338-06 head stamp ??
or would they have to be normal 338-06.

Thanks

Can't answer the other two but in my experience you don't get better brass life with AI cartridges - you just don't have to trim cases nearly as much.