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Old 01-15-2012, 05:04 PM
Big_T Big_T is offline
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Default Moon Clips for "J" Frames Information

This thread is in response to a PM resulting from my post to the thread 340 M&P speed loader problem where we were discussing how too tight speed loaders could cause your cylinder to pull off the yoke because the cylinder stop on the J Frame is not really big enough. This causes wear on the stop and yoke.

Unfortunately, the forum doesn't allow the number of images necessary to illustrate the text the way I wanted it to so I did the document as a PDF file that is attached. I leave the image placements and captions so that the entire text of the thread is searchable. I apologize because it makes the post hard to read. Please download the PDF, it's much easier on the eyes.

***IMAGE 06*** Note wear on cylinder stop.

After I posted that I had a cylinder made for moon clips installed on my M&P 340 and got the following PM from user BobR1:
Originally Posted by BobR1
I see you had a Moon Clip cylinder installed. Tell me about it. What brand of moon clips are you using? What brand of brass? How are you carrying your moon clips? Are you using a loading tool? Any issues? I would like to hear all about it.

I am thinking about sending my LCR 357 cylinder to Clark for the modification. I wanted to hear a little more before doing it however.

1) S&W wouldn't machine my original cylinder because it makes the extractor star too thin. Therefor the Ruger LCR 357 might not be modifiable.

2) The 640 cylinder took some gunsmithing to work effectively.

3) I use TK Custom 5 round moon clips and they seem to work with factory brass except CCI shot rounds. NOTE: The 8 round clips don't work with CCI shot rounds either.

4) I use a Safariland Split Six to carry the reload.

5) I use a Moonsetter tool, with improvised mandrel for the 5 round moon clips.

6) The biggest issue is short ejector rod of the J Frame not punching the cases clear of the cylinder.


As effective people know, you have to begin with the end in mind so the first thing I want to cover is what the S&W folks told me when I first asked to have the existing cylinder on my M&P340 machined for moon clips. When I enquired about it they informed me that they would not machine my cylinder because it would make the extractor star too thin and subject to bending. I then purchased, and had fitted by S&W, the cylinder for a 640 Pro which is, evidently, manufactured specifically for moon clips. I mention this because Bob may run into the same problem with his LCR 357's ejector star should he send his gun for the modification. I don't know in detail the process that S&W uses on the 640 cylinder or what Bob's gunsmith would do to his LCR's cylinder and ejector, but I mention this first as a sort of disclaimer along with the fact that I AM NOT A GUNSMITH.

***Image 01*** My M&P 340 with 640 moon clip cylinder installed. The original cylinder is below. NOTE: The 640 cylinder still fires non-moonclipped rounds flawlessly.

***Image 07*** Closeup of the 640 moon clip cylinder. NOTE: The cylinder had no smithing done on it at the factory and I initially had trouble getting clipped rounds into it because the case shoulder would catch on the edges. My good friends at the Precision Weapons Section, Marine Corps Base Quantico were kind enough to smooth that edge which resolved the problem.

***Image 10*** The 640 cylinder loaded with clipped rounds.

***Image 09*** The original 340 cylinder.

***Image 22*** The 640 cylinder (installed) and the original 340 cylinder with ejectors exposed. You can't tell from the picture, and I don't have an accurate set of calipers, but the ejector on the 640 seems a little thinner than the 340 ejector, but only slightly.

The first thing Bob asks is what brand of moon clips I use. In the J Frame I use clips from TK Custom. I had first tried to acquire the moon clips from S&W but they were, and remain, on backorder.

Next Bob wants to know what kind of brass I use. I don't reload so all the ammo I shoot is factory ammo. The last bulk buy of .38 Special I had was PMC Bronze. This works fine in all but one of the clips that I got from TK Custom. They also work perfectly fine with Hornady Critical Defense. NOTE: If you're partial to CCI shot rounds, they do not have the indentation just above the cartridge rim and won't work with moon clips.

***IMAGE 17*** Bad Moon Rising: On the left a Ranch Products 8 round moon clip filled with Hornady Critical Defense. In the center a 5 round moon clip from TK Custom with the same ammo. On the right a 6 round moon clip from Wilson Combat with Federal Hydra-Shok .45 ACP.

Bob goes on to ask how I carry the moon clips. For the 5 round J Frame clips I use a "Split Six" speed loader holder. I already had these for hauling the speed loaders for my Model 629 Safariland Comp I speed loaders. The fit of the 5 round moon clip is a little loose in the split 6, but not in danger of coming out.

***Image 27*** A Safariland Split Six speed loader holder and a North Mountain IDPA moon clip holder.

***Image 34*** The Split Six on my belt.

***Image 35*** The moon clip in the Split Six.

***Image 32*** My competition rig is a North Mountain IDPA moon clip holder here stocked with two 8 round moon clips. The stock post in this holder will NOT accommodate the 5 round moon clips and would have to be replaced. In any event, it's not very concealable, but it is quick.

Bob now asks if I use a reloading tool. There are many on the market but the one I chose, mostly for cost reasons is the Moonsetter. It's important to note that they don't sell a mandrel for the 5 shot moon clips so I've had to improvise out of my tool box as illustrated below. To de-moon rounds I use a standard 1/2" deep socket.

***Image 16*** The tool kit from left to right: Allen wrench for the mandrel screw; mandrel screw, small mandrel for 6 round .45 ACP moon clips, large mandrel for 8 round .38/.357 moon clips; the old socket adapter I use as a mandrel for 5 round .38/.357 moon clips; 1/2" deep socket for de-mooning; 8 round .38/.357 moon clip; 6 round .45 ACP moon clip; 5 round .38/.357 moon clip; Moonsetter pliers.

***Image 21*** A .38 special cartridge being mooned into an 8 round clip using the Moonsetter with large mandrel.

***Image 18*** My improvised 5 round mandrel.

***Image 19*** Full 5 round clip with improvised mandrel.

***Image 20*** De-mooning .38 special brass from a 5 round clip with improvised mandrel and 1/2" deep socket. NOTE: this is a little ungainly, but given the limited frequency of loading and unloading clips it suits my purpose. I'm sure a more enterprising soul could come up with something much better.

***Image 15*** De-mooning .45 ACP with the small mandrel and the 1/2" deep socket.

***Image 36*** I keep my mooned rounds in a little parts box like you can find in the hardware or fishing section of most stores.

Lastly Bob asks if I have any issues. The first is that if the rounds are too tight in the clip you can have the original problem of the cylinder coming off when you try to eject the rounds. I had this with 2 of the 10 clips I got from TK Custom and subsequently don't use those clips. I loaded and tested my clips before use to ensure feeding and extraction were flawless. NOTE: If the rounds feel tight in the cylinder DO NOT FORCE THEM!

The main problem I have is that when you eject the clip, the ejector rod isn't long enough to push the spent cases out all the way. Doing reload drills at the range recently I only had one clipped set of cases fall free of the gun. I slap my ejector rod hard as part of my reload drill and the clipped cases don't fall free with the J Frame. This added a step to my manual of arms for reloading which was to grasp the clipped rounds and pull them free.

The problem is illustrated below:

***Image 11*** The cases don't clear the cylinder when the ejector rod is fully depressed.

***Image 12*** About 1/3 of the case is still in the cylinder when the ejector rod is fully depressed.

***Image 23*** My 327 "R8" with clipped rounds loaded.

***Image 24*** On my N Frame Model 327 "M&P R8", the cases are only barely still in the cylinder.

***Image 25*** Maybe 2mm of case is still in with the ejector rod fully depressed in the R8. The clips fall cleanly away when the rod is released. I've never had a failure to eject the clipped rounds in practice or competition when I slap the ejector rod.

***Image 13*** It's even less of a problem in my 625 Performance Center. With the ejector rod fully depressed the cases are completely clear of the cylinder. When the ejector rod is slapped, the clipped cases fly free of the gun usually landing a foot or two behind me.

1) S&W wouldn't machine my original cylinder therefor the Ruger LCR 357 might not be modifiable.

2) The 640 cylinder took some gunsmithing to work effectively.

3) I use TK Custom 5 round moon clips and they seem to work with factory brass except CCI shot rounds. NOTE: The 8 round clips don't work with CCI shot rounds either.

4) I use a Safariland Split Six to carry the reload.

5) I use a Moonsetter tool, with improvised mandrel for the 5 round moon clips.

6) The biggest issue is short ejector rod of the J Frame not punching the cases clear of the cylinder.

I hope that answered Bob's questions and is helpful to the forum.

Finally the stars of our show:

***Image 26*** From the left an M&P 340 with 640 cylinder installed, a Model 625-8 Performance Center and a Model 327 M&P R8
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Old 01-15-2012, 10:09 PM
BobR1 BobR1 is offline
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Location: SC Missouri
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Big T

I thank you for the time you put into this write up. Great Job. I am sure that you answered many questions for lots of our fellow readers, besides just myself.

Looks like a factory Moon Clip, No Loc 442 would be the economical way to go if you wanted to carry moonclips in a J Frame. It is just barely higher than a standard one, per the S&W web site.

I measured the Ejector Star.
S&W 638 = .070
LCR 357 = .075

The moon clips are .025

This means the Ejector Star will be .050 after the modification. As much as I like moon clip guns, this might be a problem for reliability.

My current moon clip gun selection is:

3" 625-3 Power Custom Combat with Full Length Ejector Rod Modification.

4" 610 No Dash Power Custom Combat. Barrel shortened of the back by Ron Power.

4" 686-1 Power Custom Combat, Moon Clip Conversion by Clark.

2-1/2" 310 Night Guard.

I have had others over the years. SP101 9mm, Webleys, 1917's, 25's, and other 625's. I have always liked the concept of Full Moon Clips.

Thanks again.

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327, 340, 442, 610, 629, 640, 686, brownells, cartridge, ejector, extractor, hornady, hydra-shok, idpa, j frame, model 327, model 625, performance center, ruger, safariland,

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