I hardly think that permitting civilians to own bazookas, grenades and grenade launchers would be in any way advantageous. If they were readily available, we would have nuts going around saying "When bazookas are outlawed, only outlaws will have bazookas." The same with grenades and all the rest.
There is little chance that firearms will be confiscated by the government, but many fewer people would die if they were, and it would not make us less free, just less violent and less likely to shot.