Deep Dive: Lead-Core vs. Lead-Free Bullets

Other than the presence of lead, what makes lead-core handgun/rifle ammo different from lead-free handgun/rifle ammo?

The short answer: the projectiles they are loaded with.

Lead-core ammunition is loaded with copper jacketed bullets containing soft lead cores. Lead-free ammunition is loaded with solid copper bullets. In essence, lead-free bullets are made from a different material and require a different manufacturing process than jacketed lead-core bullets

Let’s take a closer look at each of these different bullet designs.

Lead-Core Bullets

Copper jacketed lead-core bullets are made from a combination of copper and lead, which creates a bullet with a soft center and a hard outer shell. By varying the amount of lead exposed at the tip of the bullet and the thickness of the copper jacket’s walls, bullet manufacturers can design both rifle and handgun bullets that expand on contact in a controlled manner at different velocities.

Copper jacketed lead-core bullets are made using multiple different methods:

Manufacturing Method 1: Cup-and-Draw

When using the cup-and-draw method, a series of round discs are punched out of a narrow strip of copper. Each copper disc is then pressed by a series of dies. This first forms them into short, thick cups, then gradually elongates each cup until it reaches the desired length and wall thickness. From there, a lead cylinder is inserted into the elongated copper cup and both materials are forced into a series of dies. This forces the copper jacket to close over the lead core and traps it inside to take on the shape of the finished bullet.

Manufacturing Method 2: Extrusion

With the extrusion method, the hollow copper jackets are formed from solid copper slugs rather than copper discs. First, long coils of thick copper wire are cut into short cylinders. Each cylinder is then pressed by a series of dies, which forms them into short, thick, cups like the discs in the cup-and-draw method. From there, the process is the same in that the cups are pressed and elongated to the desired length and wall thickness before receiving a lead cylinder. Then, the two materials are forced into a series of dies to form the final bullet shape.

However, forming bullets in this way doesn’t cause the lead core and the copper jacket to adhere. This type of bullet is known as a non-bonded core bullet, or a “cold core” bullet. The lack of a bond between the jacket and the core can cause the two components to separate upon impact (and not penetrate as deeply).

Other Manufacturing Methods

To prevent this, bullet manufacturers use different methods of bonding the jacket to the core. For instance, some manufacturers may form one or more ribs or partial partitions inside the hollow jacket before inserting the lead core. This ensures the lead is gripped by the protrusions when the bullet is formed. Another method is to pour molten lead into the hollow jacket and allow it to cool and solidify before forming the jacket, bonding the core to the inside of the jacket. This type of bullet is known as a “hot core” bonded bullet.

Advantages of Lead Bullets

Because lead is a softer metal than copper, a copper-jacketed bullet with an exposed lead tip will expand rapidly upon impact with a soft target (such as a game animal). The pressure generated by the impact will compress the lead core inside of the copper jacket, causing the jacket to rupture and expand the diameter of the bullet. With these techniques, manufacturers can produce bullets that expand rapidly at low velocities (for use with handguns) while also producing bullets that expand slowly at high velocities (for use with rifles).

Lead-Free Bullets

Lead-free bullets are made from solid copper alloy (rather than a hollow copper jacket with a soft lead core). They require entirely different methods of manufacturing that are both more complicated and more expensive than traditional lead-core bullets.

Manufacturing Method 1: Extrusion

To make extruded copper bullets, long coils of thick copper alloy wire are cut into short cylinders called “slugs.” Each slug is pressed by a series of dies, which eventually force it to take on the shape of the finished bullet. While this method of forming copper bullets might seem simpler than the methods used for lead ammo, it’s actually more complicated. It requires far more dyes and additional pressing sequences to form the finished bullets.

Manufacturing Method 2: Lathe Turning

Solid copper alloy bullets can be turned on a computer-controlled lathe during production, which is simpler than forming them by using dies. However, it’s also less efficient because the bullets are formed by removing metal rather than pressing slugs. Because of this, turning copper bullets on a lathe produces more waste than pressing them.

Advantages of Lead-Free Bullets

Solid copper bullets work a bit differently than copper jacketed lead-core bullets. Without the lead core, solid copper bullets lack an exposed lead tip. This means they don’t have the internal pressure created by the lead tip and core when they impact a soft target (decreasing the expansion). In order to make solid copper bullets expand on impact, bullet manufacturers rely on either a hollow point or ballistic tip.

Due to their construction, solid copper bullets often expand in a far more controlled manner than jacketed lead-core bullets with wider expanded diameters. Beyond that, they often retain significantly more weight and thus penetrate deeper than even bonded core bullets.

Solid copper bullets can also be designed to fragment (rather than expand) upon impact. This is called a “frangible” bullet. This type of bullet is useful in situations where over-penetration of the target might present a danger to other animals or humans (because it breaks up into several small fragments after impact). Because each of these fragments have significantly less mass and inertia than the original bullet, the fragments won’t penetrate as deeply. This also makes them ideal for home defense, where you don’t want the bullet to penetrate through the target and accidentally hit a loved one.

On the other hand, when hunting dangerous game animals such as grizzly bears, rhinoceros, or Cape buffalo, hunters sometimes want a bullet designed for as much penetration as possible. These hunters may use a type of lead-free bullet called a “monolithic solid.” This type of bullet is made from a single piece of copper and features either a round nose or a flat nose with no hollow points or ballistic tips. This enables the bullet to have as much weight as possible with no expansion. Thus, this type of copper bullet will produce a very deep and straight wound channel that can easily punch through bone.

Even though copper jacketed lead-core bullets remain the gold standard for most shooters today, solid copper bullets generally perform just as well. But unlike lead-core bullets, there’s no environmental hazard.

Lead or Lead-Free: Which is Best?

Due to recent studies surrounding lead-free ammunition, hunters are slowly coming to accept it as a viable alternative to jacketed lead-core ammunition. Its performance is equal to that of lead-core ammunition, and even surpasses it in some cases.

Today, ammunition manufacturers are starting to offer lead-free ammo in a wider variety of calibers, cartridges, and bullet weights. In a few years, the popularity of lead-free ammunition may eventually surpass that of lead-core ammunition, as hunters become aware of the potential health hazards and known environmental hazards of using lead ammo.

However, the fact remains that traditional lead ammunition is much cheaper than lead-free ammunition. Because of this, they both present advantages to shooters with different goals. As long as you follow the law, the decision is up to you.