Tuesday, October 18, 2011

Making Bullets (cast)

In another section we went over how to load your own ammunition. This one is different. This is how to make your own bullets. From (nearly) scratch.

First up is cast bullets. These are far more commonly found made at home than jacketed ones. As with making most things, you need equipment. In this case, you need moulds, a furnace, a sizing press, and lube.

The first thing to keep in mind is that:

It’s important for me to make that clear, because when lead is heated it gives of toxic fumes, and the only way to cast lead bullets is to heat lead. Getting it too hot can cause serious health problems.

First, let’s look at the Furnace. For most home setups, the furnace is a commercial electric lead pot. These can get quite hot, but usually not quite enough to create the poison gas in enough volume to worry about. They have a thermostat on them to regulate the temperature and a little valve on the bottom for putting the lead into the mould.

The Mould is nothing more than a block of steel with a hole cut into it in the shape of a bullet. This block is mounted in a pair of wooden handles so the entire thing looks a little like a pair of pliers. Where the lead goes in makes the back of the bullet, and that part is normally covered by a small steel plate with a hole it over the bullet shaped hole. When the lead cools, this hinged place it rotated out of the way, shaving off the excess lead and leaving the back of the bullet nice and flat.

The standard tool for doing opening the mould cover is a stick. You don’t want to use anything metal. The softer metal will deform and eventually chip or break off. This can be bad when you have a pot of molten lead in the area.

Some moulds will have one cavity, while others will have two, three, or four.

The next phase is the sizing and lubing of the cast bullet. You need to wait for them to cool off for this. Smaller bullets cool faster.

Because the mould can change size as it’s heated, not all bullets coming from the same mould will be exactly the same diameter. For this reason, and to just be careful in the first place, the cavity is a fraction larger than the bullet should be. To fix this, the bullet goes through a sizing press. This is nothing more than a steel ring of the right diameter that shaves off any part of the bullet that hangs over. While the bullet is in this press, a small amount of lubricant is smeared into channels in the bullet. These channels are called Grease Grooves. This grease is basically wax and petroleum jelly and feels sticky to the touch. It can come in a variety of colors and some people make their own.

The purpose of the lube is to help the bullet slide down the barrel and to keep the hot gasses from melting it. Lead bullets are limited to about 1500 feet per second (450 m/s) because at greater speeds they begin to melt from the friction on the barrel of the gun.

Some bullets, usually for small rifles, have a thing called a Gas Check. This is a small copper cup that fits on the back of the bullet and is added in the sizing phase. The purpose is to add a small layer of protection to keep the hot gasses from damaging the bullet in the barrel. They are not used in most pistols.

The lead can be adjusted in many ways. The most common is purifying it or adding tin or antimony to it. Pure lead is very soft. It’s so soft that it can be used like a crayon to color on paper, and it can be marked and deformed by a fingernail. Dropping a lead bullet on a desk will deform it as well. A bullet made of pure lead will splatter like a water balloon if it hits something hard enough to resist it. Note that a bullet resistant vest will slow it down gradually rather than stop it dead. By resisting the bullet, I mean something like a tank or solid stone wall. Even metal targets can splatter a lead bullet.

Tin or antimony are added to make the lead harder. This is a fine line, because too much of the other metal can result in poorly performing bullets due to weight or imbalance. One substance used quite often is linotype. This is a very hard alloy with a very low melting point and a density similar to lead. It makes very hard bullets. The bullets are actually too hard to be fired on a regular basis. They will damage the barrel of the average gun.

So, where does one get lead to cast bullets? Parking lots and city streets. I was on wheel weight patrol for most of my life. Anytime I found a loose one, I brought it home and tossed in the bucket. The weights go in the pot, then the impurities float to the top where they are skimmed off with a steel (not silver) spoon. It’s also possible to buy lead from gun stores with indoor ranges. They sweep out the lead from the bullet traps and refine it or sell it as is.

Casting things other than lead is possible. Lead is melted to a liquid, then that liquid is put into the mould. In theory, anything that is liquid could be put into a mould and allowed to harden. The obvious fiction bullet is silver. The Lone Ranger had them, and anyone wanting to kill a werewolf will probably look into them at some point. As luck would have it, someone did the research on that already, by actually making silver bullets. See here for how it turned out.

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