Finding the right 10mm moon clips can really change how you experience your big-bore revolver at the range. If you've spent any time shooting a Smith & Wesson Model 610 or one of the Ruger Super Redhawks chambered in 10mm Auto, you already know that these little pieces of spring steel are pretty much essential. Without them, you're stuck poking spent casings out with a pencil or hoping they gravity-drop, which isn't exactly the "tactical" or "efficient" vibe most of us are going for.
But there is a lot more to these clips than just being a piece of metal that holds six rounds together. If you've ever had a clip bend in your pocket or found that your favorite brand of brass won't quite snap into place, you know there's a bit of a learning curve. Let's dive into what makes these things tick and how to avoid the common headaches.
Why 10mm Needs Moon Clips Anyway
The 10mm Auto was originally designed for semi-automatic pistols like the Bren Ten or the Glock 20. Because of that, it's a "rimless" cartridge. In a semi-auto, the extractor hook grabs the groove at the bottom of the case to pull it out. In a revolver, however, the ejector star needs a rim to push against to get the empty shells out of the cylinder.
When you put a 10mm round into a revolver, there's no rim for the ejector to catch. This is where 10mm moon clips come in. They act as an artificial rim, holding all six rounds together in one unit. This allows the ejector rod to push against the clip itself, clearing all the empty brass in one motion. It's also what makes reloads so incredibly fast—you're dropping one big unit into the cylinder instead of fumbling with individual rounds.
The Struggle with Brass Compatibility
One thing nobody tells you when you first buy a 10mm revolver is that not all brass is created equal. Even though the "10mm" designation is standard, the actual dimensions of the extractor groove near the base of the shell can vary slightly from one brand to another.
If you're using Starline brass, for example, you might find that it fits perfectly in your 10mm moon clips. Switch over to Federal or Winchester, and suddenly the rounds might feel loose or, worse, they won't snap in at all without a fight. This happens because the thickness of the metal on the moon clip is fixed, but the width of the groove on the brass isn't always the same across every manufacturer.
If the fit is too loose, the rounds will "jiggle." This might not sound like a big deal, but when you're trying to drop a loaded clip into the cylinder during a competition or even just for fun, floppy rounds can hang up on the edges of the chambers. Ideally, you want a fit that is snug enough that the rounds stand up straight but not so tight that you have to use a hammer to get them in.
Choosing the Right Material
Most 10mm moon clips are made from spring steel, but you'll see them in a few different finishes. Blue steel is the most common and generally the cheapest. It works fine, but it can rust if you live in a humid climate or if you leave your gear in a sweaty range bag.
Stainless steel clips are a bit more expensive but offer great corrosion resistance. Then you have the high-end "nickel-plated" or "nitrided" versions. These are often preferred by competitive shooters because they are slicker, making the loading process just a tiny bit smoother.
The most important thing, regardless of the finish, is the thickness. Most standard clips are around .030 to .035 inches thick. If you're having trouble with your brass fit, sometimes switching to a clip that is just a few thousandths of an inch thinner or thicker can solve all your reliability problems.
Don't Forget the Tools
I can't stress this enough: do not try to load and unload 10mm moon clips with just your bare hands. Well, you can, but your thumbs will be screaming at you after about three cylinders.
Loading the clips (often called "mooning") is usually easier than unloading them ("demooning"). To get the empty brass out, you really need a demooning tool. It's basically a small metal tube with a cutout that allows you to twist the brass out of the clip's grip without bending the clip itself.
If you bend a moon clip, even just a little bit, it's basically junk. A bent clip can cause the cylinder to bind, making it nearly impossible to pull the trigger. It can also cause light primer strikes because the clip absorbs some of the firing pin's energy instead of letting the primer take the full hit. Using the right tools ensures your clips stay flat and functional for a long time.
Carrying Spares and Storage
If you're using your 10mm for woods carry or self-defense, how you carry those spare 10mm moon clips matters. Because they are relatively thin, they can be fragile. If you just toss a loaded clip into your pocket with your keys and change, there's a good chance it'll get stepped on or sat on, leading to that "bent clip" issue I mentioned earlier.
There are dedicated moon clip holders that clip onto your belt. These are great because they hold the clip securely by the center, protecting the rounds and keeping the clip flat. For a more casual day at the range, even a small plastic pill bottle or a dedicated storage case can keep them from getting banged up in your bag.
Reliability and Light Strikes
Every once in a while, someone will complain that their 10mm revolver is "misfiring." Before you go blaming the gun or the firing pin spring, check your 10mm moon clips. If the clip is too thin for the brass you're using, the cartridge can move forward just a hair when the firing pin hits it. That tiny bit of "cushion" can prevent the primer from igniting.
It's always a good idea to test your specific combination of clip and brass before you rely on it for anything important. Most of the time, the clips work flawlessly, but since the clip is essentially part of the gun's headspacing system, it's the first place you should look if you're having ignition issues.
Final Thoughts on the 10mm Experience
Shooting 10mm out of a revolver is a blast. You get all the power of the "centimeter" round without having to chase your brass across the range floor—the 10mm moon clips keep everything right there in a neat little package.
Sure, they require an extra step during your prep time, and you'll definitely want to invest in a decent demooning tool, but the trade-off is worth it. You get faster reloads, easier brass recovery, and the ability to shoot 10mm (and often .40 S&W, depending on your revolver) with total reliability. Just keep them flat, match them to your favorite brass, and you'll have a much smoother time at the firing line.