Today the published version of the bump stock ban came out, and it demands destruction of the devices. Owners are encouraged to destroy their property themselves, or they can turn them in to ATF offices. This isn't a buyback like people surmised. There isn't a grace period to register, each bump stock must be destroyed.
Bump stocks are now considered contraband machine guns as regulated under the Gun Control Act of 1968. Possession of one is a felony. Owners have 90 days to destroy each unit.
Gun right losses probably would have been worse under Hillary, but they are certainly taking a beating under Trump. It's very disappointing to see.