An interesting small article at the Gateway Pundit site concerning an IRS and ATF raid by armed agents on a Great Falls, MT gun store. What was seized was
All Form 4473s – documents that record buyer’s information during firearms transactions.
Gateway Pundit would have you believe this is the first stage of our government seizing all our guns ... maybe they are right. There could be a simpler, and less sinister explanation.
Driving south from the Alberta, Canadia, border, the first city of any substance you encounter on I-15 is Great Falls. Various establishments in GF have had a quiet, unadvertised relationship with Canadians who like guns but cannot obtain them in Canada.
It is nearly impossible for a Canadian to legally buy or possess a handgun - automatic or revolver - in Canada. Some GF entrepreneurs have stored handguns for Canadians who travel south for the winter and have bought handguns in the States but cannot lawfully take them home. The owners drop them off in the spring on their way north, and pick them up again on their way south in autumn.
It is possible that those agents were acting on behalf of the RCMP, who have no jurisdiction in the US. It may be that the store in question is suspected of selling handguns to Canadians who've used questionable documents showing them to be US residents and/or citizens. Perhaps several weapons bought there by seeming 'Americans' have been found smuggled into Canada.
If I were guessing, this is where I'd start.