what ammo brand is the best for long time storage? and which ones should you stay away from?
also what is the longest you should store ammo for?

I consider [i]long term storage[/i] almost an oxymoron [;)].

Buy 5.56mm ammo by the case and use the oldest first.  Note that the surplus ammo on the market is just out of [i]long term storage[/i], some more than 20 years.  Universally shoots fine although some of the very old South African M1A2 no longer meets M193 Spec (if it ever did).

Milspec ammo, with sealed primers and projectiles will store best.  It'll also store best in sealed containers.  But in the last 5 years I've fired WW2 vintage ammo that was in wooden cases and cardboard boxes and Vietnam era 5.56mm which was just in magazines in a foot locker.

-- Chuck

I go for Win Q3131A first when I find a good deal on it. Second on my list is the Federal Lake City M193. I don't consider storage as a factor when purchasing ammo.

MM419

Well , a lot of people here, myself included,
are using South African surplus which is
almost 20 years old.

I think any Mil Spec ammo that's
been stored properly will be OK.

I mentioned on another thread that I was "Making" Battle Packs using one of those vacuume food storage machines and Q3131A.

Also usin' the machine to store my Chili.

i have an armalite and i thought you should stay away from q3131 or is it q3131a?

I have an ArmaLite too both are fine Q3131A is Israeli manuf. and IMHO better

There is no reason to avoid any 5.56mm ammo with an ArmaLite rifle unless it's a match model with an excessively tight chamber.

-- Chuck