Would genuinely like to hear from a pro gun NRA type.
Not sure I qualify but I think you would think I do so here goes:
Where do you draw the line between what is and isn't a firearm? Does the 2nd Amendment allow (in your mind at least) a citizen to have a rocket launcher or a laser gun?
Cannon were not mentioned in the 2nd Amendment. Rockets were not mentioned and they were around (if relatively ineffective) when it was drafted as well. That would mean a rocket launcher would not be considered a firearm. As for a laser, the only ones that actually work as weapons are of cannon size so I would put it in that category. We have also decided that fully automatic weapons fit into the 'bigger than a firearm' category and their ownership should be restricted though they are a grey area so ownership restrictions are likewise grey. Calibers above a certain size also fit into the 'cannon' category.
What are you going to do when the technology of simple side arms develops to the point where you an take out a room full of people by pressing a trigger and letting you gun do all the aiming etc..?
Call it an IED, claymore mine or hand grenade. The comparison is obvious. The EU (and even UK) has had more problems with such weapons than the US and it only stopped when attitudes changed. If we ban such a thing and it is widely desired I expect we will be about as successful at preventing it from being sold as we are at stopping illegal drugs unless we too manage attitudes and expectations around it.