Gunpowder is one of the things you should start stacking NOW, it is not cheap (think ~$24 per pound) and there were shortages that lasted almost as long as the Great 22LR Shortage in some areas! Here are my brief thoughts on stacking maybe 1 to 3 commonly used, nearly universal application powders that are, well, Universal! :D

We will try and show that this range of powders can be reduced down quite a bit!

Pistol Powder:

Seems there are several "universal" gunpowders for nealry any caliber, there is one named UNIVERSAL, wide applications, Titegroup gets good reviews, but "Unique" seems to have ALL Bases covered, there is load data for basically anything you can name, I have seen it listed for all from 38 Special to 44 Magnum, 9mm, 45 ACP and 40 S&W, so this would work (but probably not be "optimal") for my 10mm and 460 Rowland Loads. I have a good friend who uses Unique a lot, says the biggest drawback is that the powder burns dirty... but you should clean your guns every time you shoot anyway. Great to have on hand in quantity if the SHTF breaks out!

Rifle Powder:

Lots of guys really like H4895, and IMR 4895, Hodgdon and IMR both make this Mil-Spec powder that is useful in anything from an M-16 (or civilian AR-15) up to the mighty AR-10 (.308 or 7.62 x 51) and more. So it is quite adept at "prepper" uses, as this set likes the semi-auto versions of the military hardware. I do too :D
Varget gets a lot of mentions for a universal rifle powder, but I've seen that mainly in hunting loads, like the bolt guns. You need to DYODD but this is just a guide to "narrow it down" to a few for each application. But H4895 was originally a 30-06 powder for military use, even though that cartridge is now mostly a hunting round. The 30-06 is a longer case version of the .308 cartridge. Actually, the .308 is a shorter version of the 30-06!

As you can see there are a few powders that can "do it all" for some people...

This is what would be preferable for SHTF. You could buy a minimal selection, in large quantity, to minimize headaches and mistakes. Reloading is quite an art, it is a Scientific Art but I do not recommend getting too "ARTISTIC". Stay with the book loads, the secret is to get a good ACCURATE Load for your application, not the hottest or fastest. 55 and 62 grain bullets are very common for 5.56 ammo, and the military spec stuff is plenty hot. Staying "middle of the road" is safe, economical, and sensible. Plus it is easier to find the proper components. Having common and cheap(er) components is a key in the SHTF preps regimen, it will also make it easier to barter in a situation where these items ar scarce. Just be extra careful dealing away something that can be used against you!
But that is a whole other discussion.

Next installment will cover the rest of the ammunition components, Brass (preferably your reclaimed cases) primers and bullets.

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