H.F has small plastic ammo cans on sale for 3.99.I bought one to see if it was water and air tight, and it is not. Since I am so cheap I have been thinking of a cheap way to maybe put something around lid to make it air tight. Has anyone bought these and made them air tight?

I haven't done it with the plastic ones but have with metal ones, try running a bead of RTV gasket compound around the lip in the lid where it seals. Just be sure to let it completely cure before you close the lid, that works on the metal ones so it may also work on the plastic ones. I have a couple of those but just use them for organization and didn't really care if they were waterproof so I have never tried it with them.

I have some of the HF cans but mostly use them for organization and more end up with tools stored in them than ammo

they are just small for ammo in any quantity.

I use the MTM boxes more to store ammo not positive those are air tight but they are definitely low air exchange and I keep them stored inside nearly all the time

ARC 5 and 8 are good sizes for storing shotgun shells and such in any bigger than the 8 and they get too heavy when loaded with shotgun shells or ammo
after the crates
the AC11 is our most used size can you can get a days ammo and mags , mag loader and such in to take to a shoot
or plenty of ammo for a hunting trip with choke tube wrench and spare chokes

the ACDC30 divided crate is nice is your going to a multi gun shoot.

I just buy surplus steel ones. Got a guy that has a contract with ft Campbell and gets all they have. So they are in the best shape I have ever seen and also best price.

I have several of the HF plastic ammo cans. Use them mostly for ammo storage in my walk-in closet.

But, I have one rigged up that holds a 6v rechargeable battery that runs my Spartan cell camera. I strap it to the tree..usually below and behind the camera....works well. Been in use for over a year...don't leak, but it must stay upright.

the 38 cal plastic ones are good for weasel boxes if you use the snap traps

I have found that the metals ones ARE water PROOF, but the plastic ones are not.

Those HF ammo cans are not waterproof. If you set them upright they will shed water though. If you can catch them on sale they go for 2 or 3 bucks and that's probably what they're worth IMO.
If you have an Army Surplus close you can usually find decent waterproof ammo cans for 5 bucks a piece or so.

In your dreams or mine anyway! Steel Cans are running at least $20 for surplus., and new ones at Wally world are about the same.

You're living on the wrong side of the state. LOL.

Was by there today. I was a dollar off, they're $6 a piece. The 50 cal boxes are $8 a piece. Gaskets look good.

I scored some padded military "ammo" cans that originally held night vision goggles...more than I really need.

I noticed that Walmart now calls them Field Boxes, not ammo boxes.

Last 20 mm I bought were under 20. 30caal were 8 and 50 cal I think we're 12. But this is the guy that gets them 26 + pallets at a time.

Same here as BigBob gas found.

I guess it's good to buy from one of the main guys that sells them to the surplus stores. Prices are better without the shipping and middle man.

I spray seals, O-rings and gaskets with WD 40 or silicone. I also group ammo types into small plastic ammo cans, then put inside milsurp cans. I do that to quickly grab a certain type or variety for range trips.
When I head to range I take 8 to 10 ammo types for .22 LR for example.

I have a bunch of various sized ammo cans I got from one of those Mail order type places, very cheap, FREE FREIGHT!
Brain Fart! Can't remember the name of the outfit. Sgt Major? Will add name if it comes to me. Sorry.

Major Surplus.com

50 cal cans, $10

I use them Harbor Freight cans for all sorts of things. They are pretty solidly built for the price, and they are water resistant, not water proof, says so right in their description. I have my portable aerator in one, thermocells and refills in one, air hose ends in one, etc... and I use them for ammo too. Very handy to empty shotgun shells into for shooting clay pigeons or in the dove field. There are a lot of uses for them. Pretty good buy for $3.99 ea. You can't beat their $6.99 shipping either. You couldn't hardly drive across town to a store for that.

https://www.harborfreight.com/030-caliber-ammo-box-63135.html

just to add HF's Apache cases are as good as any hgih dollar case ive used. I carry telescope equipment, expensive eyepieces and other optics in there and they are absolutely waterproof and bombproof.. They really are great for the $$$
HF has come a long way from what they once were. Ive worked with tools all my life and made a living with them. Trust me, you see a ton of HF stuff in shops these days