Well lets see...1000 rounds of 9mm weigh around 30lbs depending on loose or boxed. so 10K would be 300 lbs. Good luck being mobile with 300 lbs of 9mm for your hand gun and 1000 rounds of 308 weighs around 52 lbs...so 10K rounds of that is another 520 lbs...if you go 223 you can roughly halve that down to around 250 or so. Just through all that in your bug out bag sling over your shoulder and hustle to safety :)
I always chuckle when I hear of 1000s of rounds per person or per weapon being stored in someones basement or safe for the stuff hitting the fan day. Sure buy in bulk for target and fun, but don’t think you want to figure out how to move around a storage of a 1000 lbs or more of ammo. Real inconvenient and makes you a big target for the guys that don’t have any!
My generic recommendation is a few hundred (200-500) .22 shells, 100 or so hand gun and 100 or so rifle. Plenty to survive with, still be mostly mobile and deter the average bad guy scenario. Any plans to send a few thousand rounds down range defending your home, is probably misguided unless you happen to have a mini-gun or something :)
You guys just don't understand modern urban warfare.
Jack Sparrow and 40,000 Headmen
So I turned around and 40,000 headmen hit the dirt.
Firing 20 shotguns each and man it really hurt.
But luckily for me they had to stop and then reload.
And by the time they'd done that I was heading down the road.