i've also bought a scope off ebay with no problems and it was opened by customs also i got it no problem.right now i'm in the process of buying a inline muzzleloader from a guy in michigan,and the only way he can ship to me is ups the others refused him flat.
the only thing a canadian needs to clear customs for a muzzy is a certificate from the canadian firearms center.this certificate preregisters the gun to the guy in canada that makes it legal to import it.muzzleloaders are not even considerd a firearm in the states [got the email from the atf ]so as long as the muzzleloader has the certificate a canadian can bring it thru the border no problem.
the problem is usps and the other shippers have so many rules and codes that they can't know them all.and that is the most frustrating part off the whole thing.
go to this link then scroll down to page 2 paragraff C
http://www.access.gpo.gov/bis/ear/pdf/ccl0.pdf
here it says that their are no restrictions on muzzleloaders with calibers under 20mm are no controlled for export.11mm is about a 45cal.and if it is not controled for export it can be shipped EAR99 [no liecence required]
even with this info usps and others still refuse to mail or ship muzzleloaders just goes to show u that sum people are egnorant and pig headed.