I recall reading that one can order a .50 cal barrel out of the US, as long as the barrel is not chambered, i.e. .50 BMG!
Once in Canada the chamber can be machined................................let's say in .50 BMG, then a gunsmith of your choice can mate the barrel up to an appropriate action.
I may be wrong, but may be worth looking into.
No he's not
Via ATRS because 50cal barrels can be exported from the US
I'd love to know what the trick is.
Lothar-Walther (USA) said they can't get them out, chambered or not due to an export ban on anything .50 cal