Actually, more than one question. First regarding dash numbers; at what point did the factory stop using tool steel action parts and start using softer steel? Or, am I already wrong about that? Second, are the Model of 1989 marked specimens the only one you can use .45 auto rim cartridges instead of moon clips or do I have this wrong also? Thanks in advance, Bob.

To your second Q, all the .45 ACP 625s can use .45 AR.

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In answer to your first question the only significant change in the steel of internal parts was discontinuing case hardened forged hammers and triggers. Thy were superseded by metal injection molded parts (MIM) about 1997. Automobile cam shafts have been MIM parts for a very long time. They go round and round rubbing on other parts far more than S&W hammers and triggers and have held up very well.

As Erick wrote, all S&W .45 ACP N frame revolvers will fire .45 Auto Rim. So will Colt New Service and 1917 revolvers. Taurus used thinner .45 ACP moon clips so their .45 ACP revolvers do not have enough clearance between the rear of the cylinder and the recoil shield for .45 Auto Rim.

Thank you for the good information. I see a lot of 1911 shooters turn their nose up at MIM parts and never read any information from them about actual problems with MIM parts.

There are many that would be surprised to discover that the gun that they been shooting and enjoying without concern, has MIM parts that they were unaware of.

Case in point... S&W 3rd Gen pistols, always see high praise for them... "built like tanks", "Solid"... despite the MIM parts.

But for S&W revolvers... MIM becomes a dirty word.

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Conrad
SWCA #1830 SWHF #222

In a perfect world all Smith triggers and hammers would be made the old way with case hardening and a hammer mounted firing pin nose. (That's the way many of us older folk think anyway) BUT, the truth is that the new MIM stuff is as strong or stronger than the old forged hammers and triggers. As far as which model 625 is better? Maybe not so much about which is better but which can you find. That's the way it works in my part of the country anyway. I own a 625-8, A JM model and love it. Would I like an older model? YES! But I have never seen one - - EVER. I am willing to put up with a few features I don't really like in order to shoot ACP in a Smith. OH, by the way, I shoot mostly Auto Rim in mine just to be different but the moon clips as well as half-moon clips work fine.

My first introduction to MIM parts was when I purchased my Colt Trooper MkIII in the late 1990s. My gunsmith sat me down and "educated" me , claiming that the hammer and trigger were made from sintered metal and didn't respond well to a traditional trigger job since they had a thin degree of case hardening. Putting a stone to the sear contact points condemns the parts to fatigue failure. This is a leading reason why many of the older shooters/collectors have a disdain for MIM parts.

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Buffalo Bore makes some very stout loads in .45 auto rim. Expensive but good.

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Sorry to say, your old gunsmith had no idea what he was talking about when it comes to the metallurgy of MIM parts.

"A thin degree of case hardening" is the fault of whoever was heat treating the parts, not the production process (if it's even true). MIM parts can be heat treated the same ways to the same strengths as a machined or forged part of the same material. If they cheap-ed out on the material, that's not the fault of the MIM process. There are several critical components, produced by MIM, in untold numbers of cars on the road well beyond the 200k mark that speak to this.

Sorry to get on my soap box but I hear this garbage all the time, and its totally uninformed. Look at the two stainless steel microstructures I uploaded and tell me which one is MIM and which is traditionally processed.

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AManWearingAHat quoted and responded to Iffifleman so I'm quoting both of them.


AManWearingAHat continues writing MIM parts are as strong as forged ones. Fair enough. In reply #3 I basically agreed with AManWearingAHat's defense of MIM parts. The problem is Irrifleman wrote his gunsmith was critical of sintered metal internal parts, not MIM parts. In the early 1980s Colt used sintered metal internal parts in their double action revolvers. If I recall correctly the Troopers were Mark IIs. Their sintered metal internal parts were widely criticized. Those parts were superseded by MIM internal parts in Mark IIIs. So either 20 plus years ago Irrifleman's gunsmith was not aware of the change or 20 plus year after the conversation Irrifleman does not correctly recall his Tropper's Mark number. Irrifleman did not write that he bought his Trooper new.

[/Quote]If I recall correctly the Troopers were Mark IIs. Their sintered metal internal parts were widely criticized. Those parts were superseded by MIM internal parts in Mark IIIs. So either 20 plus years ago Irrifleman's gunsmith was not aware of the change or 20 plus year after the conversation Irrifleman does not correctly recall his Tropper's Mark number. Irrifleman did not write that he bought his Trooper new.[/QUOTE]

Let me clarify. My gunsmith (Bill) was an old style gunsmith/gun dealer. When he died in 2007, he still had NIB Colts, Smiths, and High Standards from the 1950s on. When I purchased my NIB Trooper MkIII in about 1998, it had a manufacture date of about 1976, if I remember correctly. I had the chance to select from any number of handguns that he stocked (he purchased from his distributors and resold at market prices), ranging from: Colt Diamondbacks, 3-5-7s, an original Trooper,a few Pythons, a S&W Highway Patrolman, or the MkIII that I chose. To the best of my knowledge, there was never a Colt line marketed as a MkII.

Regardless, the MkIIIs were among the earliest firearms to utilize injection parts, which I am referring to (correctly or not) as MIM. The MkIII series revolvers (circa 1970-early 1980s) just don't hold up to stoning. Fortunately, after forty plus years, MIM technology has improved to the point where the parts may hold up to a stone when having a traditional trigger job done.

Fortunately, I have never had to send one of my pre-IL Smiths in to any shop or S&W for a trigger job. The one current S&W that I do have (with the dreaded lock and MIM parts) has an acceptable trigger that should improve with use. Sadly, few of the current generation of gunsmiths are true gunsmiths, they are more part swappers. Unfortunately, the masters of the trade typically took their trade and skills with them.

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MIM is a sintered metal part.

While powdered metal is used in both processes, sintered metal uses larger particles and is formed by compaction. MIM uses smaller particles of metal powder, is mixed with a binder (removed later in the process) and injection molded.

As a side note the original Dan Wesson revolvers also used some sintered metal parts.

Adios,

Pizza Bob

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Moonclips are one one of greatest innovations for revolvers ever developed. Once you use them, you'll wonder why all revolvers weren't designed for their use. If you're not a reloader, 45 auto rim is expensive and not nearly as available as 45 acp. The BMT moonclip tool is the best one, and you'll forget the price after you use it. 45acp revolvers are really fun shooters.

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Without apology I am not a Colt man. However I do apologize for not reading Wikipedia before posting. According to them:

Irrifleman is correct. There was no Colt MK II. The Colt MK III with sintered metal internal parts was introduced in 1969. It was discontinued in 1983. The Colt MK V replaced the MK III. MK V had cast internal parts.

So ... both Irrifelman and his gunsmith were correct.

I remembered the 8" MK III that I bought new about 1981 had sintered metal parts. I did the best trigger job on it that I could but compared to S&Ws its trigger pulls it still stunk. Stoning the internals did not cause any problems in the short time I owned it.

Your not understanding that it is not explains your post. Not to worry. I get corrected all the time and am better for it.

There are a couple of tricks for loading moon clips. One is to buy a tool. I was going to buy one but saw online how to build one. A bolt, washer, board, lever arm and done! Ingenious actually. But I did not build that either. Instead, I was using a pair of water pump pliers, or slip joints. While using it I realized it opened quite large and had a rounded grip to grab pipe. I grab some moon clips, ammunition and my pliers and voila they loaded quickly and easily. A bit of pipe to uncoil the empties and your good to go.

Kevin

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You're the one who completely misunderstands these two manufacturing processes. The primary difference between parts we would traditionally call sintered parts and MIM parts is the use of a binder and an injector rather than pressure (typically a hydraulic pres) to form the green part(s).

MIM parts are then treated to remove the binding material to form the green part. Both parts, regardless of how they got to their green part form, are then sintered together, making them both sintered parts. After green part formation, the processes are identical.

Sintered parts can, just like MIM parts, achieve 99%+ density at similar strengths and have the same heat treatments applied assuming the process is well controlled. Colt was likely trying to cut corners, and not sintering their parts to full density to cut costs and time which is common for parts that will not require the full material strength.

Per Encyclopedia Britannica and every basic metallurgy textbook.

Sintering- the welding together of small particles of metal by applying heat below the melting point.

Another two steel microstructures. Sintered this time. Pick out the sintered one.


Powder particle size affects the sintering time and temperature decisions. It will not affect the driving thermodynamics that drives the densification process. Rougher powder is used in applications where cheaper parts are being made that do not require the full strength of the material (rougher powder with less controlled size distributions and morphologies are much cheaper but produce more porous microstructures for a given sintering treatment time). They can be made to work, but at longer sinter times, higher temperatures, or both. It becomes an economic trade off between feed stock price, processing price(s), and the requirements of the final part. There is nothing inherit to the processes that precludes them from making high quality parts for firearms. It's all in the cost/quality manufacturing compromises made

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I'd be far more concerned with how these guns shoot than the metal that is used in making them. I have two of these revolvers, the newest one is about twenty years old. I have no idea what sort of metal they are made of and never gave it any thought, as if it makes any real difference in the field.

As for Auto Rim brass, it's not expensive and it's easy to find. Call Starline. Opinions vary, but I like it far better than using moon clips, tool or not.

Which is just fine. Industries pay people with my skill set to care so you don't have to It does ultimately make a difference, but we make the decisions and the compromises so the end user doesn't have to see any of it.

Exactly what I said; it doesn't matter. I'm unfamiliar with the term skill "set", but will assume it's simply "skill".

Moon clips, did some say moon clips, I like moon clips!

610, 610 w/40cal, 45 ACP, 986, 686 40cal, 686 38 Super, 940, custom 629 into 38 Super 8 shot. I bought my first 625 full moon clips for .19ea, by the 100! THE GOOD OLD DAYS!
jcelect

My 686 .357 is cut for moon clips. I will hopefully be receiving a package in the mail tomorrow with a couple of mainsprings to experiment with so I can get it back into action. I bought it used and it has a lot of light strikes.