Yes, arms can be many things. The United States Supreme Court addressed, in the Heller decision, that "arms" includes anything that can be used in defense of self, family, community or country. This was read mostly as "legitimizing" that the right to bear arms is at it's core a right to self defense. Also, BTW, infringement via restrictions on ammunition, magazines and other essential parts of "arms" are clearly illegal.

BTW the "bigger gun" argument is, and always will be, wrong. A superior force is not created by numbers or hardware. Not alone. Had that been true 240 years ago we'd still be ruled by the crown of England (as would most of the world). We had neither numbers nor superior weapons. This pattern is repeated throughout history.

But the focus on things is all wrong. Mass murder isn't caused by things. It is caused by sickness and evil. More death can be caused by explosives than guns. The worst mass murders in modern US history used vehicles, explosives, or both. When he sickness and evil take over, the means will be found.

There has always been evil. But why, today, are there so many people who see the need to murder? When the NFA was passed in 1934 the number of school shootings was zero (likewise churches). Then, as now, the majority of homicide was associated with other crimes, usually "organized" (and in 1934 that organization had grown exponentially as a result of another federal ban of a thing, alcohol).

Instead of demonizing the obvious fact that THINGS don't commit murder, and ask WHY PEOPLE commit murder, we'll again have countless debates and pass new laws that will have no positive effect. Until we stop this madness and focus on the people, and specifically what is driving them to murder, we'll see more children die and more wasted lives.