Here are some crime statistics:
https://www.census.gov/compendia/statab/2012/tables/12s0306.pdf
2009 - 10,639,000 crimes committed. Of those 15,200 murders. So murders are .001 of all crime. The most accurate numbers I have seen for crimes defensed with a gun is about 104,000. So of that 104,000 we could say 104 were lives saved by someone with a gun. Far less than your ridiculous 2.5 million, and also less than the number of accidental killings with guns. So guns do more damage than good.
The statistics are clearly telling, and there is indeed a problem with gun violence in America.
But your 'solution' is no solution, if your 'solution' is more gun control, or prohibiting the carrying of a gun by citizens, the constitutionality of which not withstanding.
You're focusing only on the symptoms of the problem, without addressing the actual cause – and more gun control and restrictions will do nothing to address the actual cause of the problem.