Tannerite and small arms is the second.
Well, no; the systems oppressing you would not have lasted so long if amateur chemistry and bloodlust could topple them. For one thing, everything you can do is less than a rounding error at the scales on which "the powerful" operate, but even if it weren't, killing powerful people just leaves the boot on your neck empty for the next available foot to fill. The names and the nations may change, but ultimately the problems remain because, and I feel that this is something we really need to keep in mind before we go try to wage an actual War on Those Bastards,
the problems with oppressive systems are a product of the system and not the people in it and even bad ideas are bulletproof. You can't gun down the profit motive or explode neoliberalism, and the holes left when you try will always be filled by whatever's maximally profitable (and thus minimally compassionate) because that's the most stable configuration of the system. Those bastards you're imagining holding at gunpoint literally can't afford to be scared into being nicer on any long-lasting basis.
There are ways to actually fix the problem, but one of the reasons our current dystopia is so resilient is that it channels all the Internet Tough Guy impulses of impotently unhappy dudes toward people rather than policies, and as above, so below: people are replaceable, from the C-suite to the factory floor.