In a world dominated by high-capacity semi-automatic pistols, revolvers still have a loyal following. Known for their simplicity, reliability and the fact that they’re not prone to jamming, revolvers have a number of advantages over semi-automatic pistols. However, speed of reloading is not one of them. Fortunately, moon clips offer a solution that addresses this drawback by making revolver reloads quicker and more efficient.

What Is a Moon Clip?

A moon clip is a thin, star-shaped metal disc, typically made from spring steel, designed to hold multiple rounds together as a single unit. Moon clips are most commonly used in revolvers chambered for rimless semi-automatic cartridges like 9mm, .40 S&W and .45 ACP. Because these calibers were originally designed for semi-automatic handguns, their cartridges lack the rim that revolvers use to extract spent cases.

Moon clips ride inside the indented groove in the case, and function like a cartridge rim to set the headspace for the cartridge when chambered. Revolvers using rimless cartridges cannot be fired without moon clips. While primarily used with rimless cartridges, moon clips can also be adapted for use with traditional rimmed revolver cartridges such as .38 Special and .357 Magnum. However, using them in rimmed revolvers requires that the cylinder be specially modified to allow the clip to sit flush without altering the headspace.

A Brief History of Moon Clips

Moon clips were born out of necessity during World War I. When the United States was preparing to enter World War I, it was desperately short of material, jumping from a 30,000-man army to a projected 1-million-man force. Colt and other contractors could not fill the need for the issue handgun — the 1911 .45 Government Model. Smith & Wesson developed a thin sheet-metal clip to take the place of the cartridge case rim, neatly solving the problem of using the cartridge in a revolver. The moon clip was born, providing the necessary .05-inch headspace.

This simple innovation allowed rimless .45 ACP cartridges to be reliably used and ejected in revolvers, which solved a major logistical issue. While initially designed for military use, moon clips quickly gained popularity in competitive shooting circles and later found a niche in self-defense.

How Moon Clips Work in a Revolver

Loading and unloading a revolver with moon clips is a straightforward process. The moon clip holds the cartridges together as a single unit. During loading, all rounds are inserted simultaneously into the cylinder with one motion. When the revolver is fired and it is time to reload, a single push of the ejector rod extracts the entire moon clip with the spent cases attached, ensuring a quick and easy reload. 

The moon clip provides a firm platform that the ejector cannot pass. This prevents any individual casing from slipping past the ejector star, which is a common issue in traditional rimmed cartridges if the revolver is not handled properly.

The moon clip is stamped from thin spring steel with a shape designed to maintain a secure grip on the cartridges.

The moon clip is stamped from thin spring steel with a shape designed to maintain a secure grip on the cartridges.

Types of Moon Clips

There are several different types of moon clips, designed to accommodate various capacities and cartridge types.

  1. Full moon clips hold the full number of rounds required to fill a particular revolver’s cylinder. This is the most common type used for self-defense and competition.
  2. Half moon clips hold half the number of rounds, typically three for a six-shot revolver.
  3. Two-round clips hold only two rounds, allowing for more flexibility in tactical reloads.

Each type has its own advantages, but full moon clips are generally considered the best for quick, complete reloads.

Benefits of Using Moon Clips

Moon clips offer several advantages over other reloading methods like speedloaders and speed strips. They allow empties to be unloaded as a unit and reduce reloading to a two-step operation, significantly speeding up revolver operation.

Faster Reloads

Because moon clips hold the rounds together as a single unit, you can insert all rounds into the cylinder at once, significantly speeding up reload times compared to loading rounds one by one.

Positive Extraction

Moon clips prevent individual spent casings from becoming stuck under the ejector star, a common issue with traditional revolver reloads. This makes ejection reliable and quick every time.

Better Tactical Advantage

For defensive use, moon clips offer a quicker option for topping off your revolver. Unlike the function of a speedloader, the cartridges are never separated from the moon clip — all the rounds stay attached to each other and to the moon clip even when the revolver cylinder is closed for firing. This has some advantages over a traditional speedloader.

Drawbacks of Using Moon Clips

Despite their advantages, moon clips do have some drawbacks.

Potential for Damage

Moon clips are typically made from thin spring steel and can bend easily if mishandled. A bent moon clip can cause the revolver to jam or misfire.

No Partial Reloads

With moon clips, you cannot perform partial reloads like you can with traditional revolver cartridges. If a moon clip is in place, it’s an all-or-nothing situation — either all the rounds are ejected, or none are.

Compatibility Issues

Not all revolvers are moon-clip compatible. Rimmed revolvers often require modification to accept moon clips.

Choosing the Right Moon Clip for Your Revolver

Choosing the right moon clip depends on several factors, including your revolver model and intended use. The necessary cylinder modification to accommodate the use of a moon clip can be part of the original factory design of the revolver or can be done as an aftermarket modification by a qualified gunsmith. Some models, like the S&W 327 and Ruger GP100, come factory-equipped to use moon clips, while others require cylinder modifications by a gunsmith. Additionally, using high-quality moon clips made of durable materials can reduce the risk of bending and malfunction.

Moon Clip Tools to Maximize Performance

Loading and unloading moon clips can be challenging without the right tools. Some useful tools from Revolver Supply Company are highlighted below.

  • Moon Clip Tool with Included Arbor: Makes it easy to load cartridges without bending the clips.
  • Tube Style Unloader: Simplifies unloading live rounds or spent casings.
  • Moon Clip Holder Single Post Tall Belt Holder: Holds two moon clips for quick access during range use or competition.​

Best Practices for Using Moon Clips

To get the most out of moon clips, it’s important to handle them with care and use the proper tools. Investing in a specialized loading and unloading tool can help prevent damage to the clips and ensure that they remain in good working order. Bending or warping can easily occur if the clips are loaded improperly, so utilizing tools like the ones above can significantly improve reliability. Additionally, when storing moon clips, avoid tossing them loosely into pockets or bags. Instead, consider using dedicated moon clip holders or carriers that keep them secure and protected from bending.

Regular practice with moon clips is also essential. While moon clips can dramatically improve reload speed, they require a slightly different technique compared to using loose cartridges or speedloaders. By incorporating moon clips into regular range training, you can build the muscle memory needed to handle them quickly and effectively. This practice ensures that, whether you’re using moon clips in a competition or a self-defense scenario, you’ll be able to maximize their speed and reliability.

Are Moon Clips Right for You?

Moon clips have come a long way from their humble beginnings in World War I revolvers. Today, they offer an efficient and effective solution for revolver reloads, whether in competition, self-defense or recreational shooting. While moon clips have their drawbacks, such as the potential for damage and compatibility concerns, their benefits — including faster reloads and positive ejection — often outweigh the negatives. 

Ultimately, moon clips are just another way of loading a revolver. Whether they are right for you depends a lot upon your shooting and carry habits, as well as your tactical training. By understanding how moon clips work and using the right tools, you can take your revolver shooting experience to the next level.

 

This article is a compilation of previous articles authored by Scott W. Wagner, Bob Campbell and Duane A. Daiker.