Yeah, the 2A part is specifically addressing the "equipped" part, not the "trained" part. "Well-regulated" meant (among other things) that the militia could be "turned out" with little notice and be already equipped with their own private weapons.
Ironic that the libtards are screeching about "weapons of war" on America's streets. The right to own & bear "weapons of war" is exactly what the 2nd Amendment guarantees.