nothing wrong with you weapons choices if they work for you....a more daunting task would be the logistics of food, water, medical supplies, sanitation, etc for such a large group of people in the event of a meltdown. sounds like you need to plan for a platoon sized unit....and prepare accordingly.
I'll tell ya' what,
......Re : people who aren't FIRST AND FOREMOST focused on the logistics you call out,....and instead obsess about firepower, and firepower alone ?
They'll more then likely be SUPPLYING those who did with arms and ammo, and the greater majority posthumously, I'd venture.
"Well , we got guns,....let's go get some." ......totally predictable.
As is their subsequent (and self expedited) demise.
GTC