I like to think in terms of how many years the ammo must carry me until reliable resupply.
For me, I plan on 10 years of no ammo available. Therefore I plan the following:
For my AR I expect to fire 180 rounds a year for proficiency, so 1800 rounds per gun for practice. I also plan on 4 combat loads for self-defense (210x4= 840 rounds) total is 2640 rounds per AR—say 2700 for spoilage etc.
For my handguns, I plan on 100 rounds per year for proficiency training, so 1,000 for practice. I also plan on 4 combat loads for self-defense (4x60=240 rounds) total is 1240 rounds per handgun.
For my tactical shotgun, I plan on 50 rounds a year for proficiency, so 600 rounds for practice, my combat loadout is 25 slugs and 25 double ought buckshot. So 4 combat loads would be 100 slugs and 100 buckshot. total is 800 rounds.
For my over under 12 gauge hunting shotgun, I don’t need to practice, so 25 rounds per year should suffice for hunting waterfowl and any ground critters that may remain in my local forest once people start hunting in earnest. total is 250 rounds mixed load of 4 shot and 6 shot.
For my.22, I plan on using 1200 rounds per year for proficiency, so 12,000 rounds for training, and another 30 rounds per year for small game hunting for a totoal of 12,300.
Don’t forget the cleaning and maintenance supplies for a 10 year period. Fortunately, I already have most of this, and in some cases greatly exceeds my expected need (.22 for example).
I definitely have a legacy supply for my kids.
That's barely bare proficiency.
Before the latest ammo run, I averaged 200 rounds a month rifle and 300 rounds a month pistol. (granted I shoot with two separate defensive groups and also teach a weekly Monday night session).
As a result of the ammo famine and increased cost, I am at half that now, 100 rounds each pistol and rifle per month, supplementing with every dry fire tool out there I can find.
My 'get me through the drought' stash is about 5000 in each caliber.
That’s the investment I’m thinking. I told my 24 year old son I was buying it as much for him as me. My AR15.
For me, I plan on 10 years of no ammo available."
and there it is...