I own several different calibers and types of weapons. Ammunition Storage is not a problem. These were Surplus Military acquired over the years from local Flea Markets. $5 to $8 each, based on size. They’re used for bulk storage of various calibers in their original packaging. Inside a controlled environment, away from AC and Heating vents. I’ve stored ammunition , like Richgcoop, for decades in them. Open storage is not good.
Purchased from Wal Mart. Made by Remington, Winchester or who ever. Individual locks. They run about $20. Each, you can stack them, bolt them together. I use them strictly for lower quantities of ammunition for a few hundred rounds or so. Duct Tape over the exposed holes and they’ll do the job. The ammunition is in the original boxes.
I’m not a big fan of plastic containers by themselves.