Depending on the state, you may encounter difficultly purchasing ammunition. NY for example, requires all ammunition sales to go through an FFL dealer, even online transactions must be shipped to one for a background check at point of sale. Other border states require state id for purchase and i do not know of a single online retailer that will ship to a PO box. Then of course, each state has a raft of legislation regarding firearm/ammo possession, some making Canada's gun laws seem tame and pale by comparison. At this point, with the CDN dollar being so weak, prices, except for bulk ammo, are on par, if not more expensive than what you can find in Canada... In short, "The juice ain't worth the squeeze".