Some stock pile insane amounts others keep very little on hand.
I have a thousand or so of each caliber I have a need for, i dont see a need for more than that since I dont shoot a lot.
And then i have probably 5000rds of 22lr.
I keep more 22lr because if shit did ever hit the fan you could carry a lot of it easily.
5000 rds of 22lr is about 37lbs, 5000rds of 9mm is 130lbs, 5000rds of .45 is 250lbs.
Makes a big difference if you gotta grab a bag and go.
Shortages happen when people think they need to panic and buy every fucking thing they can, even shit they dont have a need for.
Mostly when gun grabbers get in office.