What? Is there something explosive in that box???
It is a press, as simple as a mechanical press used in garages! No way they would be right to ask for your PAL!
I bought mine at Cabela's In Scarborough and brought it back with me. The only thing to watch is the personal exemption. If you stay more than 48 h in the states, you can «import» up to 400$ of merchandise, so no problem with your press.
Even components is at the limit: bullets or brass is not an ammunition so.... But I would not try.
My 2 cent