Frequently Asked Questions

The extractor groove diameter on cartridge cases is the most important part of fitment into a moonclip. There is no SAAMI specifications for the extractor groove and each manufacturer makes them as they want. The following list gives you a great example. This is why the diameter size of the brass is critical to proper loading, unloading and fitment. Cartridge diameter too big and moonclip too small causes the moonclip to bend. The cartridge should rotate within their respective place and wobble slightly when all cartridges are loaded.

ammo chart FINAL 2

Brand of Ammo/Brass    Groove
.38/357                            Diameter
Armscor                              .365
Starline                               .366
Fiocchi                                .368
W-W Brass                         .372
PMC Brass                         .372
Rem Golden Saber Nkl      .374
Speer Blazer Brass            .374
Remington Brass               .374
Federal Brass                    .374
Hornady Nkl                       .375

This photo will give you an idea of what we mean.


Use the search filters menus on the right hand side of the Moonclip web pages to assist you on the proper moonclip to purchase.
If you are unsure about how to use moon clips for your revolver, or wondering which moon clip to use, call us. See the Contact menu tab.

How do I load and unload cartridges into the Full Moonclip?

Video on the Resources\Videos menu tab.

What brand of brass works best in your .025 Thick - Full Moonclips?

Federal or Remington & others makes works the best with the .025 thick Full Moonclips, which fit all the .38/357 standard moonclip. They allow the cartridges to have some movement or wiggle so that they will fall right into the chambers once properly aligned. Winchester brass does not work at all as the groove width is too tight/small.

Starline Brass is used in specific clips that state that they are for Starline Brass.

Recently got into revolvers with a 627, and wanted to get some moonclips, but I didn't know which ones would work best with what ammo.

I reached out to TK Custom, and Eli was kind enough to give me a sample pack! So with that, I got to work with my BMT mooner.

All results are with my grip and twist strength, which should be about average male in their 20s to 30s on a BMT mooner. No modifications have been made to either the mooner, the moonclips, or the casings. All moonclips tested are 8 rounders for the S&W 627PC.


Ammo brand/type/weight: Best moonclip in my opinion
Blued: https://www.tkcustom.com/products/swn627x8-025-blue
.025: https://www.tkcustom.com/products/swn627x8-025-ss
.020: https://www.tkcustom.com/products/swn627x8-020-ss
Horn: https://www.tkcustom.com/products/swn627x8-025-ss-horn
Star: https://www.tkcustom.com/products/swn627x8-star-025-ss

PPU 38 special 158 gr SWC: .025, .020
Blued: Hard to fit last one in
.025: Firm in Firm out, wiggles.
.020: Easy in, easy out, too much wiggle
Horn: No fit
Star: No fit

Federal RTP 130 gr FMJ: .025, horn, .020
Blued: Hard to fit last four in
.025: a little hard to get last one in, but doable, no wriggle (great combo for competition)
.020: Easy in, easy out, wiggles, but loads easy (great combo for practice, possibly for comp)
Horn: Firm in, Firm out, wiggles, but less than the .020, but loads easy (great combo for practice, possibly for comp)
Star: Only fits one at a time, last one is very hard

Armscor 158 gr FMJ: Horn, star, or .020
Blued: Very hard to get in and out. Did not completely load.
.025:  Very hard to get in and out. Did not completely load.
.020: Firm strength required to get first 6 in, last two are very hard, did not completely load. 6 that fit are very wriggly and had lots of space between the rim and the top of the cutout. Likely inner diameter differences.
Horn: Very easy in, very easy out, very loose, one bullet actually was able to move across the middle and touch an opposite bullet when pinched together.
Star: Very difficult to insert, need to be done one at a time, but bullet sits firmly in place when inserted. Did not completely load

Azoom 38 special snap caps: .025, Blued
Blued: Firm in and out. wriggle.
.025: Firmer in and same out as blued, less wriggle.
.020: Easier in and out than blued and .025, much more wriggle.
Horn: Too easy, can be pushed out perpendicularly with a finger. Some rounds fell out directly.
Star: No fit.

Magtech 38 special 158gr LRN: .025
Blued: Load one at a time, otherwise, very strong grip required. Last one incredibly hard to get in.
.025: Slight firm twist. A little wriggly. Would recommend usage for training or competition.
.020: Easier twist. Much more wriggly, Can touch opposing bullet tips with slight pressure, do not recommend.
Horn: Very easy in and out, very wriggly, do not recommend.
Star: Very hard to load, can barely do one at a time. The ones which were loaded do not sit in the cylinder. Do not recommend.

Remmington UMC 38 spl 130gr FMJ: Horn
Blued: No fit.
.025: Firm twist required to get them to fit.
.020: Firm twist required to get them to fit, but easier than .025. Wiggles. Can fall out by twisting vertically.
Horn: Fits well, but one of them fell out by twisting vertically.
Star: No fit.

Winchester Target, 38 spl 130 gr FMJ: .025, .020
Blued: Very Hard to twist.
.025: Firm twist Some wriggle. Somewhat hard to insert into cylinder. Case lip catches on edge of chamber.
.020: Easy in, easy out. Lots of wriggle. Hard to insert into cylinder. Case lips catch on edge of chambers.
Horn: Too loose. Bullets slip out.
Star: No Fit

Federal Champion 38 spl 158 gr LRN: Blued, .020, .025
Blued: Last two require a firm twist. Slight wriggle. Easy insertion
.025: Easy in, easy out. Less wriggle than blued. Hangs up on the edge sometimes.
.020: Easy in, easy out. More wriggle. Very smooth insertion.
Horn: Too easy, bullets fall out. Do not use.
Star: No fit.