found at WallyBart the "outdoor products" cell phone "dry box"...
aside from holding many smart phones nicely, esp mine with leather case, such that it doesn't rattle, and it become very water resistant and fairly crushproof, i noticed something else:
it's the right size to hold fairly large calibers... in particular, it will hold 18 carefully stacked 7.62x54R, or nearly 40 .223 or 16 .308? yeah.
here's the first test:
haven't tried it with say, .22LR, but it will hold a lot.
probably good for a bugout bag, or for hunting purposes, and many other endeavors. fairly compact too.
not bad for cell phones either
there's a larger box, 1.5 liter? that can hold around 700 .40S&W, probably 600 .45 ACP, and a SHITTON of 9mm. i've been condensing cardboard boxes to these, as they are airtight, and much more crushproof/stackable. sweet.