I was talking more about a moisture or even possibly a theft issue. I don't think many people could actually destroy an ammo can without trying pretty hard. On the other hand if there happens to be a flood you don't want to lose a couple thousand rounds or have that ammo become questionable because a large ammo can's seal failed. Also if you just have it in a closet it is easier to grab one thing and run off with it than to make multiple trips for a bunch of cans. My ammo stays in ammo cans in my gun safe. So even in a fire the fire department will most likely have the fire put out before it starts cooking off. If not the bullets aren't going to make it through the ammo cans and the safe walls, they wouldn't have the pressure to.

Moisture and theft are easy to deal with.

Desiccant blocks and gently lube the rubber seal of the cans with a vegetable based lube, like grapeseed oil. For floods just put them on a high closet shelf.

Buy a solid core closet door for your bedroom and add a deadbolt. Adding that to a proper house security package (steel outer doors, window locks, monitored alarm, and dog) will slow down any determined thief.

Or get a gun safe.

Yeah, I see your point now. There really isn't too much that can go wrong with your ammo if it is in a good can, even a large one.

Got the gun safe. Unfotunately it is hard to do to much as far as a secure closet in an apartment, and gun safes don't hold too much when you get all the guns in there.

I think I read here that the best way to tell if an ammo can has a good seal is if you can open the can and immediately smell the ammo can smell. If not then the gasket may be damaged.

Testing the seal is easy. Just fill it with water and turn it over. A good seal won't let water out and obviously won't let it in either. Just remember that if you lube that seal with any oil base lube it will eventually break down.

You can put a solid core door in your apartment bedroom. Just keep the old door tucked under your bed and switch them back out when you move. Most of these inner closet doors are all the same size. For the extra deadbolt hole you drilled in the door frame just fill it with some spackle or putty and touch up the paint. They will never know.

Apartment living takes some creativity to deal with securing your weaponry, but it can be done. If you are skilled enough to build your own AR then switching doors and removing the evidence when you move should pose no great challenge.

But the very first rule is you cannot trust anyone enough to tell them you own guns other than immediate family blood relations. Cousins, uncles, step siblings, friends, girlfriends who you don't have some serious years with, neighbors, bar buddies, whomever. Tell none of them. They all have been known to burn the trusting types. Mom, Dad, real siblings, and the like are the ones who will keep your secret. Apartment living is just notorious for people getting burned.

Also go buy renters insurance. Dirt cheap and might even be free. Many companies give a steep discount if you get both an auto policy and renters policy combo. I've seen the pair actually work out less than just getting the full coverage auto policy for young people. Then take pictures of your collection and file it with your insurance company. If you get ripped off then at worst you are out $500 to replace your stash.

My house burned down back in 93 and the fireman asked me if I had any loaded guns in the house.I told them no but I had a lot of ammo stored in there.They said they didnt care about ammo as long as it wasnt loaded in a weapon.It took them 3 hours to control the blaze but during the fire the firemen relayed all of my guns(about 40) out the bedroom window of my house to my Dad and friends who took them all over and cleaned them.The news crew that was covering the fire reported that I had a "cache of weapons and ammo"in my house like I was some kind of nut(maybe true).I still have a video of that news cast.You have to love those volunteer firemen,God Bless Them,saved my family photos too and that was about it.Stick with smaller boxes and keep some here and there and dont keep them all in the house(you might not be there to toss that mother out the window.I wasnt) Get a good fire rated safe and keep it at the lowest point in the house that you can(heat goes up)stuff by the floor will usually survive with smoke and water damage.If you have your ammo in boxes down low it will probably survive a fire.Possibly keep some in the crawl space under the house,you almost never see a house burn all the way to the dirt unless its in a remote location.

Yep, there's a real dilemma. Do you put your ammo high to avoid flood damage or down low to avoid fire damage. Your local flood situation and your home layout may help ease the situation, but some places will just make you choose your poison.

An excellent source of cheap desiccant is Damprid sold at home improvement stores usually in the paint section. It's often used to dehumidify closets and small rooms before/after painting.