100 rounds is like ten minutes at the range. If you plan on staying alive for an extended period of time you need at least 10,000 rounds for every assault rifle.
How many spare barrels do you intend to stock?
Do you have the tooling and knowledge to replace/headspace them?
How many firefights do you think you’ll survive?
There’s a lot of factoring but I figure you’ll need about a half dozen rounds for every day of survival or 1500 per year in a shtf scenario. Between hunting, defending, duds, etc. You’ll use them up faster than you think.
The good news is if well prepared, you’ll get more ammo and weapons from the less prepared who think they are tough enough to attack you.
Point is... Sure more is better, just don’t expect to be alive if you’ve had to fire 100 rounds to avoid being dead. Better to have avoided that situation altogether.