A commendable idea Andy, but I agree with the others that is not for the Forum as a whole to take a position on this. personal expressions of sympathy may well be appreciated by those who have suffered from this tragedy but one thing is certain and that is that advice on gun control from a bunch of Brits would be regarded as offensive by all sections of American society.
There is a major cultural gulf between the UK (and probably much of the rest of Europe and many other countries) and the US on this issue. We find it quite incomprehensible that civilians would want to own weapons of mass slaughter while in the US, the majority of the population appear to regard it as being an inalienable right and perfectly normal. As has been pointed out above, the immediate reaction to the tragedy has been for citizens to buy more guns 'for their own protection'. Just how that is supposed to work in practice I simply can't imagine. If somebody shoots you then you are unlikely to be in a position to fetch your weapon and shoot back - you'll be dead!
Trigger happy untrained civilians with military weapons are a menace and are just as likely to shoot the innocent as the bad guys. There don't appear to be many, if any, recorded instances where interventions by heroic gun toting civilians have saved the day against deranged madmen with assault rifles but there seems to be some sort of inbuilt assumption that this is a realistic scenario. The record of supposedly trained law enforcement officers is not great in these situations either. When they open fire innocent individuals are rather prone to get hit.
Given the number of guns in circulation in the US and current attitudes, it seems impossible that any realistic curbs can be enacted, things have simply gone too far and the US will just have to live with regular tragedies on this scale however unpalatable that may be.
Something seems to have gone badly wrong in the American psyche and it may take generations before it can be resolved. People tend to think that Americans are just like us but 3,000 miles further West. They aren't, they are foreign with very different mindsets under the surface veneer. People also think that Russians are sort of East Europeans really, but they aren't either, they think in very different ways that we would not be very comfortable with.
It's a rough old world really.
Colin