>>>But it did make a difference. Out of the 25 worst mass shootings (fatalities > 8) in the US since 1984, 15 occurred since 2004 (and only 3 during the ban).
>
>I've only had a runny nose 3 times since I started carrying a red handkerchief. Therefore?
>With respect- this feels to me like GOP "experts" talking about the perils of single payer healthcare when most of what they say is divorced from real world experience.

The numbers I gave you are based on real world experience, unfortunately. And they count if you look at these events in their specific context.

>When statisticians examined the effect of the ban up to 2004 as best they could, the reluctant conclusion was that any improvement in firearm violence from the ban, was so low as to be un-measurable. Were they wrong? ...

As best they could? When you lump together all gun related fatalities, the number from mass shootings is not even a blip on the radar. Therefore, it's irrelevant. Surely, you can see the fallacy here.
The number is measurable, and very relevant, if you look at the number of fatalities per event.

>... Never mind that the latest school shootup was by shotgun/handgun, it's "obvious" that a semi-auto weapon ban will prevent it and if you disagree, you have blood on your hands.

The discussion about semi-automatic weapons comes up during events like this. That does not mean that it is a cure all. But, I can assure you of one thing: If the shooters in Las Vegas and Orlando (and not only) used only a handgun or a shotgun, there would have been a lot less victims.

>My expectation is that some sort of controls will be imposed on semi-auto weapons. Not just in the US: current suggestion in NZ is that some form of training sign-off ought to be involved. In the US there's precedent for a sales ban and very likely a house super majority, meaning even POTUS can't veto it if people insist he's a demon in the demon NRA's pocket. As to whether it will make a difference- I hope so. But I've already given the example of London passing NY earlier this year for murder rates, some involving illegal handguns that are not prevented by the UK's stringent controls, but more involving knives... and grenades now making a delightful appearance. My point is that "where there's a will there's a way" and I cannot understand the logic "lets ignore the will to do these things, instead lets remove one way we don't like." Right- a determined shooter-upper will never think of any other way of achieving their goal. Except that they will, as shown by my London example and the latest mass shootings in the US and Australia.

In the meantime, bad people in the US have easy access legally to semi-automatic rifles. That's not the only problem, but isn't that a big one?
A while back in this thread, I posted a link to the Army Field Report assessing the AR-15. That thing is built to kill people on the battlefield.

>Now maybe you have stats showing that the incidence is still lower after a semi-auto ban- in which case great, I'm all ears! Because the irony is that I'm not even arguing against a semi-auto ban, just raising simplest queries that ought to be easily covered off if the idea is sound.

An idea subjected to infinite regression never appears sound. Bill - and Aristotle - are right; some knowledge does not depend on demonstration.
*