1) Would I view it as tyranny simply if all guns magically disappeared and we were able to preclude future private ownership of such weapons without invasive searches?
2) Given the reality we live in where guns are overwhelmingly available, and the only possible way to prevent their distribution would be a police state, would I be in favor of such measures if it meant 30,000 fewer people died each year?
My answer to the second question is clearly no. I don't think that measures less than tyrannical ones would have any impact on preventing criminals and crazies from launching attacks like this, so they are to my mind a price of freedom.
As to the first question, I'd have qualms about giving the government such a complete and unfettered force superiority over the people, but would have to think long and hard about the trade-offs. In the current situation, I'm simply dismissive of legislative responses as unworthy of consideration. In the hypothetical laid out in number one, I certainly wouldn't be.