I talked to CBP and HS about taking my can to SA on safari. They suggested NOT doing it, going over should not be a problem but, coming back very well could be. Suppressor can NOT be imported and bring one into the country is considered 'importing' to them. You may be arrested and the can confiscated even if you have your paper work. That's what they told me in Atlanta when I called.
You may be able to use one from you Ph when you get there.
This sounds like sound advice, except, you are not importing a can since you didn’t buy it outside the USA. You can’t import a gun either, but you can bring your gun back with you.
Also, it’s been my experience that calling up TSA, HS or CBP, you do not get the expert advice. If they aren’t intimately familiar with the topic, it’s my experience that they just guess or err on the side of caution. These are gov employees, not attorneys.
I’m still leery of taking a can outside the USA until a very solid track record of bringing them home is established.