Question about MIM parts on gen3 5906/5903's...

Hey guys, a buddy and I both recently lucked into a couple gen 3 Smiths, and these both have the black trigger and hammer (the hammers have a cut-away,recessed part on either side, that borders on being skeletonized). He was told by someone supposedly knowledgable about these that the black parts were MIM, but I was skeptical, and now curious.
I just dug up an old article on Chuck Hawks website about the history and delvelopment of the 5906, written by David Tong,
who mentions that on the 5906, the "slide, barrel, trigger and hammer are machined forgings", and then goes on to say,
"some MIM-produced parts, such as the ejector, magazine release button, disconnector and firing pin lock plunger".
But then he goes on to referrence the "ungainly '1917 Enfield-like' rear sight ears", as seen in the photo at the top of the article, which is the version that has the silver, not black, trigger and hammer.
So, I'm wondering if these black parts are forged parts, as the article says the silver parts are.
Any info is much appreciated.......

I have a 5906TSW which appears to have the MIM fire control parts as well. There was a related discussion to this in one of the 6906 threads: http://smith-wessonforum.com/smith-wesson-semi-auto-pistols/434166-what-happened-all-6906s.html#post138584902

I have actually studied this in some detail and have come up with this observation. All flash chromed parts are forged, but not all black parts are MIM. There is a period on third generation guns where S&W used blued forged parts. These will have a profile exactly like the flash chromed forged parts. It easiest to see on the hammers, as they are both flat in the side profile. The MIM hammers are more rounded and dished on the sides. The griggers are harder to spot. The easiest way is MIM triggers will have a mold ejection mark on the side of the trigger.
The change over from flash chrome to blued occurred around the VAF serial number prefix with a few occurring on late TZxxxx serial numbers. MIM started appearing sometime after the VEHxxx serial numbers. I did this by studying guns for sale on Gunbroker and their serial numbers.

Mark IV said:

Hey guys, a buddy and I both recently lucked into a couple gen 3 Smiths, and these both have the black trigger and hammer (the hammers have a cut-away,recessed part on either side, that borders on being skeletonized). He was told by someone supposedly knowledgable about these that the black parts were MIM, but I was skeptical, and now curious.
I just dug up an old article on Chuck Hawks website about the history and delvelopment of the 5906, written by David Tong,
who mentions that on the 5906, the "slide, barrel, trigger and hammer are machined forgings", and then goes on to say,
"some MIM-produced parts, such as the ejector, magazine release button, disconnector and firing pin lock plunger".
But then he goes on to referrence the "ungainly '1917 Enfield-like' rear sight ears", as seen in the photo at the top of the article, which is the version that has the silver, not black, trigger and hammer.
So, I'm wondering if these black parts are forged parts, as the article says the silver parts are.
Any info is much appreciated.......

Click to expand...

We all love pictures here, so with that in mind.....

Triggers:
The one in the middle is MIM flanked by flashchromed forged steel on the left and blued forges steel on the right.

Note the parting line on the MIM trigger where the mold halves met. And below note the four circular indents on the MIM part visible on both sides.


Hammers:
Top is MIM, bottom two are forged steel.

More hammers:
Forged steel suprless and MIM spurred


Sears:
Forged steel in the middle flanked by MIM sears.
Note again the circular depressions on the side also, the warning to only pair with a MIM hammer.



Never heard of a MIM disconnector or ejector. Ejectors have always been steel AFAIK and disconnectors were steel then changed to composite polymer.

Cheers
Bill

Don't be afraid of MIM

I have a polymer Disconnector in a 457 that bothered me, so got a stainless one to replace it if it ever went bad, after 100's of rounds so far it appears just fine. The stainless sits in my spares if it ever does wear out

BMCM said:

We all love pictures here, so with that in mind.....

Click to expand...

Arik said:

Don't be afraid of MIM

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Wow! Thanks for the excellent pictorial Bill! I too had heard MIM fire control was actually quite desirable in 3rd gens.... any comments Bill?

ETA: Also, to confirm - all the known instances of MIM hammers have the "skeletonized" or "hollow" side profile? IOW, if one sees a "solid" blued hammer it's forged?

A couple more advantages of the MIM parts over the machined steel parts ...

MIM parts are more precise. This could be very noticeable when coming across some variability in how the trigger "ears" were machined, which does have something to do with how the triggers engaged the V-groove in the drawbars.

MIM parts are smoother. (The working surfaces, not necessarily the edges.) This is something all the armorers remarked upon in the armorer class where I first saw them. It sort of felt like someone had done a polishing job on the hammers.

I'd seen all range of machining quality in the forged/machined hammers. Surfaces that looked smooth, and then surfaces that looked like ragged shale outcroppings. The difference can be felt in the DA trigger pull. Also, there are a couple other spots where the MIM hammers are much smoother in contact with other parts.

First thing I did to my early production 5903 when I got back from armorer class? Replaced the machined parts with MIM and the installed the plastic disconnector. Nice.

The reason the manufacturing of the hammers & triggers have to be matched in the DA (DAO) guns ... MIM parts to MIM parts or machined parts to machined parts ... is that they changed the geometry when they introduced the new-style DAO (MIM) that could be used in regular (TDA) slides and frames. Trying to mix MIM and Machined DAO parts results in improper alignment of the parts. Not good. Think square peg in round hole.

The spurless carbon steel (blued/black) hammers were being used in some of the less expensive guns as they were being used up (according to that I was told when I called and asked how I'd gotten one in a parts order). Notice how in BMCM's third image the lower/right spurless hammer lacks the serrations of the flash-chromed spurless hammer? I was told this was a cost cutting measure employed while they were transitioning over to all MIM hammers. Probably some number of 457's/908's floating around with those smooth spurless machined hammers in them.

The plastic disconnectors? Better than steel, in a couple of respects (other than cost).

I was told that exhaustive in-house testing had revealed they withstood extended shooting tests every bit as good as the steel parts, if not better.

The advantages? They're smoother and more precise. Sound familiar?

Armorers used to be taught how to CAREFULLY stone/file a disconnector to correct a potential problem with the older steel disconnectors called Long Tail Disconnector. The introduction of the plastic parts eventually eliminated that from the Troubleshooting Section in the manual.

Also, being smoother on the sides and bottom of the tail ... and plastic ... the disconnector's tail could more easily ride over any machining imperfections on the drawbar's disconnector tab. Smoother from the get-go.

Now, plastic is still plastic ... and I'm told the factory did eventually figure out one potential disadvantage for the new disconnectors. Inattentive armorers.

Yep, you can't use the pin punch to push and twist on the tail to lever it around the drawbar tab in a TDA gun. It'll break, because it wasn't intended to take that sort of pressure. Runs fine as intended, though, meaning in normal use and live fire.

I like them. A lot. I like them in my guns. I think I still have a spare on a long back order from the factory, come to think of it. Might ought to call and check on it again. It's apparently not a part they really needed to keep on hand in a lot of quantity except for actual production and armorer classes.

Awesome info Fastbolt, thank you! Would you say then that MIM are the first choice, flash-chromed the 2nd, and blued the 3rd choice in fire control components?

I wouldn't say MIM is the first choice. Milled [forged] are still the best. How I interpret this is if your gun has MIM parts, it's not necessary to remove them, & put milled parts in. But to me, milled parts are always the best. Remember, the gun companies didn't start using MIM parts because they were better. They did it to save money, as it costs less to make MIM parts. MIM parts will be OK for most, but for a gun that fires thousands of rounds a year, the milled parts will be superior. If there were 2 similar guns for sale, with one having milled parts, & the other MIM parts, I would always take the gun with the milled parts. GARY

Many thanks to all for the informative replies !! By the way, I wasn't concerned or 'afraid' of the MIM parts, I was just curious. The overwhelming preponderance of info I've read on MIM in the last couple years indicates it's just fine,especially from the big-name manufacturers like Springfield,Ruger, S&W. But, this was the first that I'd heard it was actually better or preferred in some ways.
Anyway, thanks again.

N4KVE said:

Remember, the gun companies didn't start using MIM parts because they were better. They did it to save money, as it costs less to make MIM parts.

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Clearly there's a degree of personal preference here, but what I'm coming to believe is that on the 3rd gen autos, S&W's finished forged parts are not as finely finished as S&W's MIM parts are. So given an *EQUAL* degree of finish, I'd agree - forged over MIM. Your argument basically sounds like "One can make better forged parts than one can with MIM, given no constraints on time for finishing"

We're not in that case though and given the condition in which each came off the S&W assembly line, it seems like MIM out of the box is a finer finish than what S&W put on forged parts.

Put another way, if S&W were expending $X on the fire control group, it appears that what they produced for $X (or less) via MIM was a finer finished part(s) than what they produced for $X in forged part(s).


It's also worth re-emphasizing that this "analysis" is for 3rd generation S&W autos, I've not researched the revolvers or other mfg guns, etc, etc. So it's not intended as a "MIM better than forged always" statement, but a "3rd gen S&Ws with MIM are probably better out of the box than 3rd gen S&Ws with forged parts".... which leads to my question on blued vs chromed finish on the forged parts....

solomon said:

Awesome info Fastbolt, thank you! Would you say then that MIM are the first choice, flash-chromed the 2nd, and blued the 3rd choice in fire control components?

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I prefer MIM.

As far as the difference between the earlier machined parts that were either flash-chromed or blue/black? For me, it would depend on how well machined and finished the parts might be, and whether they fit & functioned together normally in any particular gun.

I've seen some really roughly machined parts, and some really nicely machined parts. When those cutters got dull (no self-monitoring computers), they could produce some nasty chatter and rough parts. Sometimes it might matter, and sometimes it might not, though. Cosmetic appearance is a far different thing than how parts actually work together.

Another thing to mention about the plastic parts is the mainspring plunger (hammer spring "cup").

Some smiths used to talk about having to smooth the edges of the older metal plungers (cups) to allow the spring coils to smoothly compress inside it during DA trigger mode. (Another instance of some are rough, and some aren't.)

Well, the plastic ones didn't have that sort of problem in the first place.

It might be prudent to keep in mind that any of the manufacturing processes - cast, forged, MIM, whatever - are only as good as the materials and quality control used.

When it comes to MIM, the molds used are a big component of providing quality parts.

We were told that S&W early on decided that the only way to control the consistency of their QC was to buy and own the MIM molds used to make their parts. Those aren't inexpensive. (I was also told that S&W wanted to keep the MIM houses used inside the US, and not out-source them to another country.)

Also, some of the small assemblies S&W has manufactured by a vendor (to exacting S&W engineering specs) have to be finished when received by the company. Final machining and finishing, that sort of thing. (I think the example mentioned to me was the manual safety assembly, if I remember right, as I don't necessarily write down such trivia, either in or out of armorer classes.)

Fastbolt said:

I prefer MIM.

As far as the difference between the earlier machined parts that were either flash-chromed or blue/black? For me, it would depend on how well machined and finished the parts might be, and whether they fit & functioned together normally in any particular gun.

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Gotcha, thanks! I guess I'm glad to hear there's no clear "winner" between the blued & chromed as I see some guns with the blued which are otherwise desirable so I'll count it a neutral.

solomon said:

Clearly there's a degree of personal preference here, but what I'm coming to believe is that on the 3rd gen autos, S&W's finished forged parts are not as finely finished as S&W's MIM parts are.

We're not in that case though and given the condition in which each came off the S&W assembly line, it seems like MIM out of the box is a finer finish than what S&W put on forged parts.

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I can sort of agree with this statement. When I had a 645 when they first came out, the trigger sucked. While it was fine for self defense use, it sucked for target use. I actually sent the gun back to S&W, but they told me "that's how they are". They smoothed it up a bit, but I still didn't like it, although the gun was very accurate. As with anything back then, I sold the gun to a friend, kicked in $100, & got something else. Fast forward to last month, & a local was selling a 645. He was a gun smith, & bought the gun from a local deputy who carried it daily. He did his thing to the trigger parts, & this gun has the nicest trigger I have ever felt on any S&W gun. So milled parts with a smith's massaging is the best combo for me. OTOH, I daily carry a Rock Island compact 45. The rumor is the trigger parts are MIM. Since I really don't know, to me it's "don't ask, don't tell". That gun has the most amazing "out of the box" trigger. Something you have to pay extra for a gun smith to do. But with that gun, 200 rounds down the pipe to prove I can trust my life with it, & I'm good. Maybe 50 rounds a year I'll fire through it. So if that gun does have MIM trigger parts, I would have to say they are finished better, & I certainly won't fire that gun enough to wear out the MIM parts. GARY

solomon said:

\Would you say then that MIM are the first choice, flash-chromed the 2nd, and blued the 3rd choice in fire control components?

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I guess I'll chime in too...

First choice here is always whatever yields a superior trigger feel.

As far as color goes, I tend to like the trigger & hammer to match and I tend to prefer the look of the flash chromed steel parts best. However, the trigger feel trumps all else in my book. I don't care how pretty it is... if the trigger is lousy I'm going to change some parts.

Here's a pic to illustrate my point and some of what Fastbolt said:


First take a look at the lower radiused area on those hammers, note that each one has two parallel wear tracks (shiny stripes) of equal length. Now go look at the first picture I posted of the sears above. The top of each sear has two shiny wear spots that correspond to those tracks on the hammers. During the DA pull the sear spring forces the top of the sear against the hammer as the hammer is rolled back.

Now back to the hammers... Looking at the difference in surface finish amongst those hammers you'll see the two steel hammers in the middle have what Fastbolt described as the "ragged shale outcropping" finish. That rough surface makes for an absolutely lousy DA trigger as the sear drags across that rough patch when the hammer rolls back. Gritty, crunchy, spoon on a cheese grater lousy!. Over on the right you see a typical example of a MIM hammer. Note the uniformly smooth finish. While that MIM hammer yields a very nice trigger as is, it can benefit from a very light polish on the aforementioned radius with an ultra fine ceramic or ruby stone. And I mean very light with a stone of 1200grit or finer, to just burnish the high spots hardly taking any color off to really slick things up.

No over on the left you see a steel trigger that had some finishing work done prior to chrome dip (and I hope before case hardening). It's even smoother than the MIM part and yields a superior DA trigger.

What about those two steel ones in the middle? Well I could polish them out but why bother when I can just swap in some MIM parts without any trouble.

In fact I did that very thing with my SSV project gun with new MIM components and that gun has the best DA trigger of my bunch which includes a couple of PC pistols. Second to that gun is my 4566TSW which I rebuilt. Not a molecule of MIM or plastic on that one aside from the grip and still nicer than the PC guns so go figure. Of course the was a bit tuning & polishing here and there so don't think I'm bashing the PC guns at all.

Plus there are some concerns with polishing that nasty a surface. The finish will be removed in that area exposing white steel and increasing the likelyhood of corrosion. Additionally, due to the amount of metal I'd have to remove to achieve a uniform smooth surface I may be cutting through the surface hardening layer exposing the ductile interior thereby accelerating wear of the part once in service. So no need to bother with that business I say! Best not to mess with it.

In the end... If I had an older gun with steel F/C components exhibiting a lousy DA trigger I wouldn't hesitate to swap in a MIM set.

Cheers
Bill

BMCM said:

In the end... If I had an older gun with steel F/C components exhibiting a lousy DA trigger I wouldn't hesitate to swap in a MIM set.

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Y'all are a veritable font of knowledge, thanks for the great pictures Bill!

Is there a forum directory of 3rd-gen gunsmiths? I have a guy I use locally but I don't know how much he specializes in 3rd gens...

For that matter, how much fitting is needed if I were to buy parts from Brownells (or elsewhere?)? I'm moderately competent to swap parts out, but uniformly bad at cutting/filing/etc - or at least not good enough to want to touch stuff this precise. (I "joke" that I'm a "measure twice, cut three times " person.)

ETA: How model-specific are fire-control sets? E.g. would the same parts work in a 6906 and 5906 and 1006? (Or does one just need to consult the parts lists and look for commonality?)

solomon said:

Y'all are a veritable font of knowledge, thanks for the great pictures Bill!

Is there a forum directory of 3rd-gen gunsmiths? I have a guy I use locally but I don't know how much he specializes in 3rd gens...

For that matter, how much fitting is needed if I were to buy parts from Brownells (or elsewhere?)? I'm moderately competent to swap parts out, but uniformly bad at cutting/filing/etc - or at least not good enough to want to touch stuff this precise. (I "joke" that I'm a "measure twice, cut three times " person.)

ETA: How model-specific are fire-control sets? E.g. would the same parts work in a 6906 and 5906 and 1006? (Or does one just need to consult the parts lists and look for commonality?)

Click to expand...

Amongst the 3rd gen TDA guns you can swap those hammers & trigger assemblies any which way so long as you pin the correct length stirrup for the gun to the hammer. For example if inclined, you could use a spurred hammer from a 1006 and install it in a 3913 given that you use the short stirrup. The parts list isn't of much help because the hammers are listed as an assembly which includes the correct stirrup for the particular model and the fixing pin. Even though the hammers themselves are widely interchangeable the hammer assemblies as listed are not.

MIM components are universally of very tight dimensions and finely finished. They require no fitting or fiddling and can be considered drop-in parts. I'll sometimes do a very light stoning on that radiused area to slick things up even more but that's just me picking nits and isn't necessary at all.

In point of fact I've had some parts come across my bench that were flat out ruined by someone stoning the hammer hooks and jacking up the angles. Probably why that stuff was on fleabay in the first place. These days I've taken to examining those things under a loupe to check for any flaws or irregularities before installing. Anyway, best not to mess with the hammer hooks or sear angles. There's no need to anyway especially so with the MIM components.

After swapping any of these bits you still need to perform a thorough safety & function check of the arm before any live firing. And when you go for the first live fire test... For the first few shots.... only load the mag with 1 cartridge for a couple shots then try loading two in the mag a couple times. You want to make damn sure after messing with the F/C components that everything is working as it should. You don't want load a full mag for a test drive and wind up putting a dotted line on the ceiling. I didn't doit but I was present when it happened once... Braaaaap! with a 1911.

As far as gunsmiths go... I only know of Karl Sokol and Novak's who by all accounts do superior work. Local smiths are, like any other professional artisan... you'll want to vet the guy before you drop off your toys.

Cheers
Bill

Nice pics BMCM. Nice illustration of how the cutters can sometimes create a rough surface on the earlier machined hammers that doesn't exactly lend itself to a smooth DA stroke. Your 2 "rough" hammers are actually quite a bit smoother than some of the ones I've come across in early 3rd gen guns, though.

I've had an opportunity to be shown by someone from the factory how the hammers could be dressed (NOT part of an armorer class), and then by a former longtime former armorer (who also made some customized Colt, S&W & Browning HP guns). Looks simple, but you can ruin a hammer with alacrity if you're not careful.

All you hobbyists and 3rd gen fans, this is something best left to someone knowledgeable about doing it.

Ditto sears. Leave them alone. Don't start mixing and matching older machined sears that have been stamped with numbers without knowing how to check for normal fit & function in any particular assembled pistol. The factory used to have "repair" sears for some models.