38/357 Moon Clip Thickness

Posted by George on 21st Jan 2016

How thick should my moon clip be for an 8 shot 357?

We get asked this question a lot and the answer applies to 5, 6, 7 and 8 shot moon clipped revolvers.

If you are reloading under the clock (ICORE, USPSA)  you want fast reloads.  If you are reloading NOT under the clock (Steel Challenge) then reload time does not matter.  If you want faster reloading times then you want a rather firm fit of the cartridges in the moon clips.

The recess or groove that's cut in a 357 cartridge is NOT part of the SAAMI specification.  Manufactures of brass can make the groove any size and change it at any time they want.

Here's what we have observed:

Winchester brass has the thinnest groove and prefers moon clips that are either 0.020" or 0.022" thick.  

All other brass (Federal, Remington for example) except Starline works well with moon clips that are 0.025" thick.

And Starline brass has a larger groove and needs even thicker moon clips to hold the cartridges tightly.  Using moon clips thicker than 0.025" reduces the space between the cartridge and the frame.  This may cause interference as the cylinder turns (not good). I know folks that have moved the cylinder forward but then the revolver becomes a Starline Brass only revolver.

Other suppliers of moon clips make them specifically for Starline brass.

When the rounds are inserted into the moon clips you should be able to freely rotate that round in it's position.

These notes apply to 357 Mag, 38 Special, 38 Long Colt and 38 Short Colt.

We offer moon clips that are black oxide coated (blued) and clips that are nickel plated.  The nickel plating is a protective coating and makes the clip a bit larger holding the brass firmer.

Also we are haply to send you samples of these moon clip for your evaluation.