(Full disclosure: This article doesn’t contain an exhaustive list of every method of making gunpowder/black powder, nor does it contain every minute safety precaution you need to take in that process. Do your research and seek out expert opinions. Proceed with caution and at your own risk.)

It’s one thing to prep for the next hurricane or tornado or economic calamity. There are a lot of really basic skills and supplies that will get you through those situations, and pretty much anyone can acquire them. But the scenarios that are truly difficult to prepare for, are the ones that involve the total collapse of our society for any given period of time. That’s because surviving those scenarios requires you as an individual, to pick up the slack of everyone else in society.

By that I mean you really have to do everything yourself if you want to survive. You have to grow your own food, heal your own wounds, fix your own gear, procure your own energy, and possibly even build your own shelter. When the commerce and infrastructure of society breaks down, you’re truly going to be on your own for a while.

Fortunately, it wouldn’t take long for a society to start functioning again in some capacity. Working together, communicating, and trading is in our nature as human beings. We’d be eager to put the pieces of society back together again. But if a particularly cataclysmic scenario comes to pass, it could take years before our world is back in business. In that time, there would be one substance that would be in short supply, and that is gunpowder.

Reloading spent shells and casings would become a necessity after a collapse, and gunpowder would be particularly difficult to procure. In the modern world, producing gunpowder is child’s play, but when society breaks down it will be an arduous, dirty, and time-consuming task. And it won’t be high quality gunpowder either. You’ll most likely be stuck making black powder, which isn’t as good as what ammunition manufacturers use now but it will be effective nonetheless. Here’s how it’s made:

For starters you’ll need three ingredients. Potassium nitrate, charcoal and sulfur. All of these ingredients should be ground into a fine powder if they haven’t been already. The ratio of these ingredients is 75% potassium nitrate, 15% charcoal, and 10% sulfur, and that ratio is by weight, not volume. These ingredients should be ground up separately before mixing. Grinding them together could cause an explosion. It should go without saying that throughout this process, you shouldn’t let any sparks, static, or open flames get anywhere near your materials.

As far as mixing them together, first add a small amount of water to each ingredient to reduce the risk of combustion; just enough to give it a dough like consistency. Now you can grind them all together with a mortar and pestle (don’t use any utensils or containers made of metal). Most people will use a ball mill to both grind up the materials and mix them together. It’s a bit safer, and will make a higher quality powder.

This moistened paste can then be pressed into a single solid mass, and as it dries you can grind it up again into tiny pellets. This is a process known as “corning.” The product this produces will burn better and will be a bit more stable and consistent, than if you just mixed all these ingredients together all willy nilly with a bowl and spoon. After that, you’re pretty much done.

In an apocalyptic scenario however, making black powder is the easy part. What would be really challenging is attaining these ingredients in the first place. Charcoal would be the easiest, since it’s fairly easy to make on your own. Willow, soft pine, western cedar, and cottonwood trees are most commonly used for making black powder.

Sulfur is bit trickier. Depending on where you live, you may or may not be able to get a hold of it in a grid down scenario. Fortunately black powder can still be made without sulfur. Simply mix the potassium nitrate and charcoal together with a 80/20 ratio. It won’t burn as well, but it will still work. Sulfur can also be substituted with iron-oxide (rust).

Your most challenging obstacle will be finding the potassium nitrate. The only natural source of this material can be found in bat guano, and I’m willing to bet that you won’t have an easy time finding that. You’ll have to make your own.

Traditionally this was done by what’s called the “French method.” You have to mix urine, manure, and straw together. Periodically, more urine is added and mixed over and over again over the course of several months to a year. Then water is poured through the mixture and filtered through wood ash, causing potassium nitrate crystals to appear, where they can then be separated.

A more modern method involves a metal drum with a drainage valve near the bottom. A screen mesh is placed inside, and manure, water, and urine is dumped in and mixed on top of the mesh. You seal it up tight and let it sit outside for 10 months. Then you drain the liquid into a wood ash filter, and let it set in a shallow, wooden or plastic container to dry. Once the water dries, potassium nitrate crystals will remain.

These aren’t the only methods though. There are countless more, so it would be a good idea to do some research and find something that works best for you. The Army’s Improvised Munitions Handbook has a recipe for making potassium nitrate that is a lot faster than what I explained above, and it also contains its own procedure for making black powder.

As you can see, making your own gunpowder can be incredibly dirty and dangerous, but having this skill under your belt is certainly empowering. Firearms are among the most useful tools in a prepper’s arsenal, and knowing how to make your own gunpowder means that you can keep on shooting no matter how long it takes for society to be rebuilt.