Of those 30k deaths, how many do you think were caused by 'high-powered firearms'? What does that even mean? The vast majority of shootings are by handguns, which is probably isn't what you're thinking of when you think of high-powered firearms.
You actually are reading the constitution backwards. The constitution not only grants explicit rights to 'the people' to keep and bear arms, but it further does not grant the federal government the right to regulate it, thus it's retained by the people per the 9th Amendment.
It's worth noting the reasoning behind the 2nd amendment: 'the security of a free state'. Everything I've read on the subject points to the idea that 'the people' need the ability to defend themselves from an oppressive government, ie 'a free state'. You can do that with pitchforks if you like (and you trust your fellow citizens enough to carry them around you), but I'd prefer to have high powered firearms.