Steve - the story I got from Customs, was that they'd run into a problem (their words) with Reamer Rentals dot com - renting reamers to Canadians - mostly B.C. - imagine that. Customs had no way (according to them) of checking that the reamers were actually returned (normal postoffice mail - zipp - gone) & therefore surmised the reamers stayed, free of 30% duty + Provincial sales tax at the time. See, their literature states if reamers are not returned within so many days, you pay the full purchase price.

Now, we have only a Federal Goods and Services tax + Provincial Sales tax + $5.00 customs handling fee. ALL goods coming into Canada via mail or truck are assessed this fee - if they don't slip through. Sometimes they do and a lot depends on the size of the package. At different times I've received brass, bullets, tobacco delivered to my door - no charges - you just never know if something is going to cost or not. Just before my Soule tang sight arrived costing me $47.00 taxes, I'd received 100 rounds of .45/70 brass with no extra charges. You just never know.
Machine parts covers a lot of this response - 'ho-hum- boring' no need to check that one category - sometimes.

I had a deal to trade rifle scopes with a chap in the Wyoming. My 8-32 for his 6-24 - straight across. No deal with customs here unless I wanted to pay taxes on the full Canadian purchase price of the scope coming in - some $150.00 worth of taxes - didn't seem worth the trade afterall. So much for Free Trade.