I did firearm import and export work via Port Huron/Sarnia for ten years, 2-4 trips a year depending on how fast I could make the paperwork roll. I did a smaller amount of brokering work for clients up until 2017. Gave up my ITAR registration in 2019. The BIS registration is dormant now. The US CBP and Canada Customs have been working together for years. They've conducted raids on both sides over unregulated parts shipments. A Dentist in Chatham committed suicide because he was carrying shipments via the ferry at Sombra, and the Post Office boxes on the US side got raided by CBP. He was paranoid they were coming for him eventually. The sad part is he hired me to bring stuff one time and it was done legally for $50! After that he opted to accumulate items at his PO Box on the US side and slip them through himself at the ferry crossing. Even shipments of parts and some related items are controlled and require a BIS/Census/CBP registered shipper to acquire an AES ITN in order to legally ship. Postal shipments that lack this number will get hung up and sometimes confiscated. The volume of mail is large, so a lot slips through without issue. That's why many US distributors refuse to send firearms related items. Most aren't registrants with BIS, US Dept. of Commerce and can't be bothered. I could write a book on the experiences. Had great people and not so great people on both sides. By using the same border crossing, at least the agents knew me after so many years which certainly helped a bit.