Please explain 'Moon Clips'


August 13, 2010, 04:09 PM
Forgive my ignorance here.... Will someone please explain what moon clips are and their function? Is there an advantage to using them in any way? I'm about to buy my first revolver and would like to know a few things before I purchase...I've checked out a few and so far,I'm pretty set on a S&W 640 stainless... One of the 640's I've checked into takes moon clips...The other slightly less expensive one doesn't...I have several semi autos but I'm not that familiar yet with wheel guns...Any info appreciated...

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August 13, 2010, 04:14 PM
Moon clips are used in a revolver to hold the cartridges already in position to be loaded into the cylinder. There is no faster way to reload a revolver.

They work best in revolvers chambered in auto pistol calibers like the .45 ACP and 10mm.

They can work in rimmed revolver calibers, but not so good due to the lack of a extractor groove for them to snap into. As a result, rimmed caliber clips are thinner, and more flimsy. It is harder to line up the rounds with the chambers without some fiddling.


August 13, 2010, 04:44 PM
The advantage of moon clips over a speedloader for reloading is that with moon clips you don't have a release which needs to be tripped or a speedloader body that need to be removed after the shells are released into the cylinder.

An additional advantage is during ejection. The moon clipped shells are unlikely to leave a casing under the ejector start.

Just curious, which chambering is the M640 in that uses moonclips?

Lucky Derby
August 13, 2010, 05:08 PM
Moon clips were originally devolvped so the .45 ACP cartridge (a cartridge intended for semi-auto pistols) could work in a revolver during WWI. Colt could not keep up with demand of the M1911 pistol so the military adopted the M1917 revolver, made by both S&W and Colt, to suppliment their supply of M1911s. since there is no rim on the ACP cartridge, the extractor pushes on the clip to extract the rounds

The original "Half Moon Clips" each held 3 rounds of .45 ACP ammo. You would drop two of them into the cylinder and you were fully loaded with six rounds. Newer clip designs are "Full Moon Clips" and hold six rounds. Drop in one loaded clip and you are good to go.

Clips have been developed for 9mm, 10mm/40S&W and ..38/.357. Perhaps other cartridges as well. They are the fastest way to reload a revolver and the only practical way to ensure reliable extraction with auto pistol cartridges in a revolver. (Yes I am aware of the S&W M547, I did say practical) .

The Lone Haranguer
August 13, 2010, 06:49 PM
Moon clips are mainly for rimless autoloader cartridges, so they can be ejected from the revolver, although clip setups for rimmed cartridges are out there too. (These would likely require machining off the cylinder face, an irreversible alteration.) You will want a tool to insert and remove the cartridges into/from the clips.

August 13, 2010, 07:29 PM
Just curious, which chambering is the M640 in that uses moonclips?

357/38+p The sku # on the S&W page is 178043...It says "cylinder cut for moon clips"...

Thank you all for the explanation and always,much appreciated...

August 13, 2010, 09:00 PM
you also do not need to use the moon clips if it is with 38/357. you can just drop the rounds in the charge holes or use a normal speed loader if you prefer, ignoring the moon clip option.

August 13, 2010, 10:25 PM
Not to be confused with Moon Bats......

August 14, 2010, 09:37 AM
Take a look at Tom Kilhoffer's website at TK Custom. There is also a video on Youtube of the machining process. As said moonclips work better with rimless auto rounds than straight rimmed cases but they both work better than speedloaders. Take a look at Jerry Miculek's world record videos on Youtube. It's hard to believe but I have stood next to him and watched him reload so fast you can't really see the reload. In most applications once a stock cylinder is machined for moonclips you cannot shoot it without using them. S&W revolvers designed for moonclips from the factory use may or may not fire reliably without the clips.

August 14, 2010, 12:54 PM
The way they are machining cylinders the aftermarket...allows use with either moonclips or loose shells. The machining is really quite interesting

Guns and more
August 14, 2010, 03:28 PM
So......can you use moon clips in any revolver? Or does it have to have a groove cut in the cylinder?

Now that I think about it, you'd have to get a revolver made for moon clips or modify one since there isn't enough room between the frame and cylinder to add the thickness of a moon clip.

August 14, 2010, 03:34 PM
So... my advice is to follow rcmodel's advice.... cannot really go wrong there.... I have a Taurus 608 that is cut for moon's and it is handy... though, like rc said, it can be fiddly to get the 357's in sometimes, still better than one at a time or speedloaders....IMO... works perfectly with the 38's though....:cool:

it requires a machinist to cut down a section of the cylinder starting roughly half way to the inside of the chamber holes... if that makes sense... then the moons have to be cut to the specs that the cylinder was cut.. this allows you to attach the cartridges to the moon clip and the chambered rounds sit in the cylinder exactly as they would without they machining or the moon clip....(the moon clip is the same thickness as the metal removed from the cylinder.)

August 14, 2010, 03:40 PM
here is a video of how they machine the cylinder for moon clips

The Lone Haranguer
August 14, 2010, 04:46 PM
A revolver requiring moon clips will still shoot without them in a pinch. The clips are for case ejection.

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