There are two things that are necessary to resist violence, up to and including genocide. The ability to resist (arms) and the will to resist. If you have one, but not the other, you are, sadly, doomed. If you don't have either, then you have doomed yourself.
And even if you have both, you are not guaranteed peace, or victory. But, at least, you have the opportunity to try.
A civil war is an ugly thing, but nearly as ugly as genocide.
All else being equal (and it almost never is) bigger bullets tend to work better.