Just like in convincing juries, convincing the public is not about truth, it is about what the uninformed can be made to believe. People feel vulnerable now to airline terror, if you have an anti BMG goal that is the best way to get it accomplished. The truth I imagine has more to do with it being a semi auto or single shot weapon (costing around $8,000) that is huge, heavy, bulky, etc that has no legit anti-gun argument. It is legal per ATF caliber guidlines and has a slow rate of fire. How can you ban such a thing and why would you want to? Play into fears. Why ? because it is truly formidable in mass and presents a threat to government trying to rule from a central authority trying to impose an absolute rule. It also sets a precedent for legaly banning weapons that fit into no pre existing 'evil' catagory like 'assault weapon'
What governments that have disarmed people in the past due is start with powerful semi auto, getting around to 'concealable' and creating a ton of legal paperwork that clearly documents who has what in the meantime through registration or fees, requirements that are state verified, etc
Things like CCW records and hunting licenses could effectively create a database on many arms. You create 'assault weapon' bans, 'saturday night special' bans etc for those too difficult to track. Of course that requires asking those that already have them to register so you know who they are, so they can avoid becoming a criminal and facing serious prosecution and continue owning thier weapon of course
Then you slowly reduce the power of the allowable firearms so that eventualy most are ineffective against high level body armor. At which point you are free to go door to door in 'buyback' programs and those wishing to oppose can't do anything about it. Your handgun or 00buck (ballistic equal to what? a .380? a .22?) would just bounce of the body armor while they return fire with highly effective weaponry your not professional enough to own. Think its unbelievable? Great Britain did it, Canada is doing it, Australia is doing it, and the United Nations is trying to urge world based small arms (guns) control.