Comparing a S&W revolver made with MIM parts to a revolver made with machined parts

[9mmepiphany]

Once all the dimensions are known and properly toleranced, making the pin type of trigger stop within the Rebound Slide work in mass production is no problem. And quicker and easier to install. You just have to remember to pop it into the Rebound Slide and Spring, with the flat end to the rear, before putting the Rebound Slide in. Anybody who has ever wrestled with a Rebound Slide knows that this can be a bit of a pain.

This is something that S&W commandeered from aftermarket pistolsmiths.

The problem with the trigger stop at the rear of the trigger guard was that they can move and block the trigger from releasing the hammer. It was a common admonition to M-19 owners, who carried that gun as a duty weapon, to remove the trigger stop completely.

The modification for some PPC shooters was to weld and file a stop to the rear of the trigger, a less labour intensive solution was to drill the trigger for a set screw; to which a piece of rubber was usually glued.

Inserting a piece of rod into the rebound slide was much easier and it could be adjusted, by trial and error, with just a file.

S&W Pistolsmiths I knew had a pre-ground Craftsman screwdriver to make installation of the rebound slide spring very easy

 

[Jim K]

I always used a plain old #2 Phillips screwdriver.

Jim

 

[rcmodel]

My homemade rebound slide tool.

Just a bent piece of 3/16" music wire with a slot in the end, and a dowel rod handle.

The bend makes it much easier to get a straight push to compress the spring.





rc

 

[Driftwood Johnson]

This is the tool I use.

http://www.brownells.com/gunsmith-tools-supplies/handgun-tools/slide-tools/s-w-rebound-slide-spring-tool-prod774.aspx

 

[rcmodel]

Mines the same deal, except I just made one instead of paying $20 for one.

They work way slicker then a screwdriver, with much less risk of marring a gun.

rc

 

[Jim K]

Hi, Driftwood,

You wrote about the old style trigger stop: "The stop is a small piece of steel that is held in place by the end of the small screw in the photo. There is no hole in the Trigger Stop, the screw simply clamps it in place."

That isn't true, at least not on my pre-17 (K251xxx); the stop has a threaded hole in it and is grooved on the right side. The screw goes into that hole and pulls the stop up against the inside of the hole in the frame where the grooves (hopefully) keep it in place. There are no threads in the hole in the frame, only in the stop itself. I took out some of those stops and made ones that fit the slot and wouldn't move, then I threaded the frame hole for a screw that would hold the stop in place. Of course, I left the stop long so I could file and fit once everything was together. Wish I had thought of the pin in the rebound slide spring, but AFIAK no one was doing that at the time.

Jim

 

[Driftwood Johnson]

Jim K

You caught me in a little white lie. I did not actually remove the trigger stop. I loosened the screw, saw that the trigger stop wiggled a bit, then tightened the screw up again while keeping it in position and making sure the hammer would still fall.

So I bow to your superior knowledge of the trigger stop.

 

[Driftwood Johnson]

Triggers

As with the hammer assembly, the MIM trigger assembly of the 617 has been substantially redesigned for simpler assembly.

As an aside, when I used to work in manufacturing companies, sub-assemblies such as the hammer assembly or trigger assembly of a traditional S&W revolver would have been assembled separately and kept in a separate parts bin from their component parts. This of course required extra paper work to keep track of the assemblies as well as the component parts. I do not know this for a fact, but I suspect when a revolver was assembled in pre-MIM days, parts would be kitted for a group of revolvers, and this would include finished sub assemblies. Just looking at the way these parts are designed, I suspect (but I do not know for sure) that kits would include the component parts of the trigger and hammer assemblies, and they would be built right on the bench at the same time the revolvers are being assembled.

On the Model 17 trigger assembly, other than the pin for the pawl, there are three pins pressed into the trigger. The Trigger Lever, (the plunger that interacts with the Rebound Slide) pivots on one pin, the torsion spring for the pawl is captured by another pin, and the last pin is a keeper for one leg of the spring. I think, it has been a while now since I had this stuff apart.

On the MIM assembly, there are no pins to press in place. The Trigger Lever, is a loose part that drops into a slot in the trigger body. It appears to be plated. And the spring nestles in a recess in the trigger body. These things can be done at any point, and need no specialized tools. The slot in the trigger body is there to insert a tool to position the spring.








The pawls are pretty much the same, they each have a pivot pin pressed into the pawl, and a smaller diameter pin for the spring to work against. As far as I can tell, the pawls themselves are not MIM parts. Notice the shape of the business end of the pawl is slightly different with the MIM trigger, because the configuration of the cylinder ratchet teeth has been changed. We will see that soon. In this view the countersink that helps guide the trigger onto the flat ended stud is visible, as well as two ejector spots.






The Model 17 trigger is serrated, and the traditional Case Hardening colors show up at this angle. I do not know if the MIM hammer and trigger are hardened, I see no colors. However MIM parts can be hardened, so I suspect they are, for wear resistance.






This view is interesting for a few reasons. Notice the rough tooling marks on the back of the Model 17 trigger (the one on the right). Tooling marks just like this can be seen on the underside of a regular hammer too, but they are hidden from view inside the gun. Peek at the rear of a S&W trigger and you will see these tooling marks. I believe these marks show that the part was broached out of a solid piece of metal, not machined. Later operations would have cut away these marks on the rest of the trigger, but they are still visible on the rear of the trigger, left rough.

We can also see that the slot cut into the Model 17 trigger goes deeper than in the MIM part. That is partially because the cavity in the MIM part has been shaped to retain the spring. We can also see the pair of grooves that the bosses on the Trigger Lever fit into on the MIM part. And we can see the actual trigger has been hollowed out a bit on the MIM part, behind where our trigger finger rests.

 

[Jim K]

FWIW, I had been told that while hammers and triggers had earlier been forged, by post-WWII period both were blanked (punched) out of sheet steel; that seems consistent with the marks on the Model 17 trigger.

Jim

 

[Driftwood Johnson]

As I said at the beginning of this thread, I welcome information by folks who know what they are talking about.

Jim, here is a photo of the back of the trigger of a K-22 made in the 1930s. This is from the era when S&W was stamping Reg. U.S. PAT. OFF. on the rear of hammers to protect their case hardening process trademark. They stamped it on the rear of the trigger too. I just never put it together about the rough broaching marks on the later guns, and the polished finish on the earlier guns. Thanks for pointing it out. Always glad to learn something new about Smiths.

This K-22 may be the subject of another photo-essay at some point.

 

[Driftwood Johnson]

Cylinder Stops



Not a whole lot to say about the Cylinder Stops, except that the MIM part from the Model 617 (on the right) was made in one step, while the conventionally made part from the Model 17 on the left required multiple machining operations to make. Ejector pin marks on the MIM part are visible. Dunno what the two little raised dots are. The slightly raised surface around the oval hole may be a bearing surface, seeing as the frame has no separate bearing surface for this part. Don't know for sure.







One related comment I would like to make at this point is I really hate the fact that S&W got rid of the screw in front of the trigger guard a long time ago. It is always a pain wrestling the Cylinder Stop Spring out of the recess in the frame that retains it.








It was much easier to disassemble or reassemble the Cylinder Stop when it had its own plunger and spring in the screw hole in front of the trigger guard. But that's the price of progress.

 

[MrBorland]

The different shape of the 617 Thumbpiece is necessitated by clearance for the key to the lock.

I missed this the first time around ( from post #81).

Just to clarify - the new style latch clears the lock, but the latch was changed in 1997, whereas the lock appeared in 2001. Several models are "transitional" in that they're pre-lock but have the new style latch. The 686-5 and 66-5 come to mind. I'm not sure why they changed the latch, then, but the new latch definitely offers more room for speedloader clearance.

 

[rcmodel]

I agree.
The new latch came along at the same time the MIM hammer & trigger did.
Well before the lock.

I think it was changed for thumb clearance, as the old style would take all the skin off your thumb joint giver half a chance.

Pre-Locks made in.
317 - 1997.
625-6 - 2000.



rc

 

[Jim K]

Golly Driftwood, you are one of the few folks who knows that the "REG.U.S.PAT.OFF" on those parts actually refers to a trademark not a patent* and that the case coloring was registered as protection against cheap Spanish revolvers. (And that trademark protection is the reason S&W still colors those parts, though they wouldn't have to for hardness.)

*Because patents expire - trademarks do not.

BTW, when it comes to photos of the insides of guns, you are absolutely tops. I have seen many professional photos that didn't come anywhere near yours for clarity and focus.

Jim

 

[Peter M. Eick]

I can only add great photography of an interesting subject.

 

[Blade First]

"I love the in-depth photos and now have a better understanding of why pistolsmiths think so highly of the new MIM action parts in S&W revolvers "


I'm afraid in your zeal for the subject that you've jumped to a wholly unsupported opinion. MIM parts range from short-lived trash [some not much better than pot-metal parts, for instance] to engineering changes for major mfrs. which promise a penny or so margin per unit. There isn't a major mfr. that hasn't had problems with MIM parts.

Are they "fixed"?

Perhaps...but why should I plan on leaving firearms to my heirs which might be burdened by inferior parts or designs, especially since the majority of same are the result of political compromises?

Given the price of current-production S&W revolvers, I'd rather purchase older-production models which I know will be superior revolvers, where hand-fitting, quality of materials, history of performance and associated collectability will give me some assurance that my money is well spent.

Your mileage might vary...

 

[9mmepiphany]

I'm not a personal fan of MIM, so there wasn't any zeal involved.

I was relating what very creditable pistolsmiths, who specialize in S&W revolvers, have told me about the benefits of the the inclusion of MIM parts to S&W actions.

They are seeing much more consistent triggers, prior to action work, then they were with the older S&Ws. The best older revolvers were much better, the worst were much worst and the median were not as good...so overall, the quality of the revolver actions have improved with the MIM parts.

They still switch out the parts for competition guns, but those are guns which the owners will wear out over the course of a few seasons

 

[Jim K]

If the kiddies are done crying about MIM, the thumb piece was indeed changed for the reason rcmodel says. If you look at Post #1, you will see that the old one is quite close to the curve of the frame so if the thumb is held high, the thumb can contact it in recoil. S&W had tried earlier to change the thumbpiece in heavy recoil guns (remember the J-Frame thumb piece variations?) but had not carried that over to the entire line.

Jim

 

[ATLDave]

If you look at Post #1, you will see that the old one is quite close to the curve of the frame so if the thumb is held high, the thumb can contact it in recoil.

That matches my personal experience. I could shoot .38 wadcutters all day long out of my Model 19 with the old-style latch, but just a few mid-range .357 would have my thumb bleeding. I had to change out the latches (and do a little filing to dehorn the bottom edge of the new latch) to solve the problem. The old latch looks cool, but the new latch is ergonomically better for many shooters.

 

[Nom de Forum]

I love the in-depth photos and now have a better understanding of why pistolsmiths think so highly of the new MIM action parts in S&W revolvers

Blade First - I'm afraid in your zeal for the subject that you've jumped to a wholly unsupported opinion. MIM parts range from short-lived trash [some not much better than pot-metal parts, for instance] to engineering changes for major mfrs. which promise a penny or so margin per unit. There isn't a major mfr. that hasn't had problems with MIM parts.

Are they "fixed"?

Perhaps...but why should I plan on leaving firearms to my heirs which might be burdened by inferior parts or designs, especially since the majority of same are the result of political compromises?

The impression I am getting from this thread is that MIM does offer many advantages for simplicity of manufacturing and in individual part and part assemblies. This type of simplicity in the component parts of any machine can benefit durability and reliability but it can also limit modification and performance. So I would appreciate any comments Blade First, 9mmepiphany, Driftwood Johnson, JimK, rcmodel, MrBorland, and anyone with extensive experience have about how the older best quality S&W revolvers are superior to the best of the MIM versions in ways beneficial to the shooter other than fit and finish . Can anyone make a credible case in measurable shooting performance the older guns are better? Is it more difficult to accurize and tune the MIM guns in comparison to the older designs?

Driftwood Johnson you can add my voice to the chorus of praise for your photographs and accompanying comparative analysis!

 

[Peter M. Eick]

I will give you my opinion based upon shooting targets. I get a bit fanatical about collecting and tend to collect many samples of the same gun. My current (permanent?) focus is the 38/44 HD.



This is about 25 guns out of date. I do shoot many of them so I have a feeling for the sample to sample variation over decades.

Before the 38/44's I was into 610's. I had many of them but I did not really take pictures before I switched over to collecting 38/44's.

I also only shoot 50 shoot groups, offhand 15 to 25 yrds.




vs.



So with my bona fides established I will make the follow brash statement.

On average, if you are looking for an accurate reliable revolver, you are more likely to get a good one made in the MIM age then in the pre-numbered period.

Modern MIM guns from S&W are just more consistent and accurate than the older ones on average. I say that from comparing not a one off specimen, but dozens of the same model made over decades. The older ones are nicer fit and better finish and are a dream to shoot (long action) but at the end of the day, the modern ones are more consistent, tighter tolerances on the parts that matter like the barrels and cylinders.

Yes individual guns from the pre-numbered era will take on any modern gun for accuracy. And yes individual modern guns are absolute dogs and QA/QC should be fired for letting them go out the door but still we need to talk averages and dozens of the same gun vs. dozens of the same gun in the modern era.

My feeling is that this occurs because many parts in the pre-numbered era were made by craftsman and fit together by craftsman. Every one of us knows we have good days, and bad days. This happened back then also. So if you get a good day gun great, bad day gun, well it is what it is. Modern guns are more of a jigsaw puzzle and they just drop the parts in with minimal fitting. There is less impact of the craftsman on the final product.

Now just because I recognize the modern guns are more likely to be better. it does not mean I like to collect them. Give me my 38/44's and I am happy.


Ok let the mudslinging begin!

 

[Nom de Forum]

Wow! Peter that is impressive. Thank you for providing an opinion formed from extensive experience. I am sure if anyone slings mud your way it will not stick.

 

[Jim K]

It is rare to find someone with that degree of experience who is not a factory employee. Thanks, Peter.

Nom de Forum, much of the modification and tuning of the old guns was nothing more than removing tool marks and deburring parts. Most of those who worked on S&W's spent time stoning triggers and DA sears and rebound slides to remove the rough edges left by the milling machines making cuts across the work. With MIM, the part that comes out is smooth; there are no milling cutter marks, no burrs, nothing to stone or smooth up.

As to fitting, what fitting? MIM parts don't need fitted; that does not mean that tolerances have been relaxed or that the guns are loose, It means that MIM parts are right, out of the MIM process, so nothing needs to be fitted.

So my response is that the new guns really are better from any direction except that of the hand polishing seen on some older guns. And that could be done, if the buyer were willing to pay twice the current prices.

Jim

 

[MrBorland]

how the older best quality S&W revolvers are superior to the best of the MIM versions in ways beneficial to the shooter other than fit and finish

On average, if you are looking for an accurate reliable revolver, you are more likely to get a good one made in the MIM age then in the pre-numbered period.

Peter expressed my thoughts well here. Fit and finish aside, and on average, I think the newer ones get the nod for overall performance. And even new examples with so-so actions can be easily tuned to very excellent performance.

 

[Old Fuff]

Peter expressed my thoughts well here. Fit and finish aside, and on average, I think the newer ones get the nod for overall performance.

Ah.... But some of us don't want to set fit and finish aside. It's a critical component to excellence. As for "overall performance", I don't see enough of it to make a critical difference.

And even new examples with so-so actions can be easily tuned to very excellent performance.

Probably true, but older revolvers (especially those made before 1947) seldom need extra attention, and I doubt that those made between 1947 to 1998 (with the introduction of MIM lockwork ) can't be tuned to at least equal those made later. While the material and fabrication method changed, the parts didn't - except where it was necessary to accommodate the new lock.

Should I desire (and I don't) I can set up most 1947-98 S&W revolvers with MIM parts, plus a modified hammer.