> > mandatory training and licensing
> I don't think this is reasonable or politically feasible.
I agree that it's not politically feasible, but am curious as to why you don't think it's a reasonable requirement. No one reasonably complains against people have to complete a training course in order to get a driver's license (or to the requirement of a license itself). Both activities require a proper understanding of operation and safety, and operation and safety failures of both can easily result in severe injury and death. Ignoring the political issues around this, I'm entirely baffled how the idea of this requirement could be considered unreasonable.
> > restrictions on ammo purchases
> Not sure what good this would do in reducing gun deaths. You would be hitting target shooter pretty hard for not much gain.
In the recent Las Vegas shooting, the shooter reportedly fired several hundreds of rounds. Presumably if he had been legally limited to owning, say 50 or 100 rounds (more than enough for self defense in the home, and sufficient for most hunting outings), fewer injuries and deaths would have occurred.
I will grant the argument that mass shootings are by far the smallest percentage of gun deaths; you only need a single round to commit suicide or for a child to accidentally shoot him/herself, or a few rounds to kill your family, so this sort of limit wouldn't help there.
Regarding target shooters, I think we can easily make an exception for ammo purchased and used at a licensed gun range, as long as the ammo purchased for target use does not leave the gun range. (Shoot it or lose it, basically.)
But I think at the end of the day the question is "what can reduce unlawful harm without putting an undue burden on lawful use?" ... and I think ammo purchase/ownership limits pass that test.
> > restrictions on ... magazine size
> I don't see how this would be very helpful and always strikes me as something advocated for by people who don't understand guns very much. It's part of why you see such opposition to it.
Perhaps not, and I'll admit I'm certainly no gun expert. But a reload or magazine swap isn't instant, and in the case where a shooter is actively engaged with law enforcement, having to pause to reload after (say) 10 rounds instead of 50 could easily mean fewer deaths. Again, if I apply the test I suggest above, I think it passes.
I'll also admit that I personally do not believe in the need or fundamental "right" of private firearm ownership. I'd be fine with a repeal of the 2nd Amendment with an explicit directive to allow the individual states to make their own gun laws, and would be fine if my state banned private gun ownership entirely... so I'm comfortable with many more restrictions than probably most people are. I have no interest in owning a gun and find the vast majority of the reasons people use to argue for gun ownership to be entirely disingenuous. At the end of the day, aside from minor exceptions, the only real reason is "I think they're cool and fun and I and just want one". Which is totally fair and legitimate, and I wish more people would admit that's the real reason they support private gun ownership.