Penalties for subverting the existing background check laws are appropriate. Penalties against the manufacturer for the use of their product is not appropriate. If you want to go down this road, then you need to be willing to be accountable as an administration for the deaths caused by every weapon that was made available to insurgent factions overseas. The US government is complicit in the dissemination of more firearms to bad actors than any other agent or governing body. If you want that to be the benchmark of responsibility, then you must bear responsibility for your own actions in this regard.