Metal Injection Molding - MIM - Why The General Dislike?

[fyimo]

Well I'm old so most people would think I hate MIM parts and I don't as long as they are the right parts and in the revolver for the right reasons. If they are there where they shouldn't be for just most cost cutting purposes then I don't want them.

Like others have said I hate the IL because it was never needed and a complete surrender by S&W to the Government.

 

[robk]

MIM is currently used mostly as a cost cutting measure that should have no effect on performance. True or not, it is here to stay. Now, should I avoid any new pistol just because of MIM parts? Guess I can't because there are some nice new models I want to own. I would pesonally perfer that all pistol parts were made of forging, but that's not going to happen. Sometimes you be be able to replace the MIM parts out with forged parts. But MIM will not go away, that's for sure.

 

[BlueOvalBandit]

The firing pin should be bar stock, which would be far cheaper than MIM or forged.

Those 2 processes are for "shaped" parts like a trigger.

IMHO

Frame mounted firing pins are Ti and are WAAAAAAY better than hammer mounted when it comes to getting trigger pull down, they can go lower.

I like well done MIM, S&W does it right. It only take 5 minutes to do a trigger job as far as polishing goes, no more cutting new sears to length etc. S&W MIM is just wicked evil hard.

From an economic standpoint it may be cheaper to produce the physical part, but the initial tooling costs are really high.

 

[Invictus357]

The main problem with MIM is the name.

If MIM was called "Cold Forged Injected Colour Case Hardened Alloy with Big Hammers" I really think it would have been more accepted by Smith and Wesson purists.



From my own experience, my MIM 686 has been sublime. I also like the dirty look to it as well.

To be quite frank, if it wasn't for the internet I would never have heard of MIM..or penguin porn for that matter.

 

[DCWilson]

As suggested above, it's mostly just a question of perception and a concern over potentially diminished quality. MIM parts can break (though sometimes only if you force them to), and the broken surface looks a little like fine-grain pot metal. Not an encouraging sight.

I have never had a problem with a MIM part and can attest that the actions on my guns that have them are among the smoothest have experienced. If I didn't know the phrase or have to look at their rather drab appearance, I would not have any negative judgment on them at all.

But despite my approval, I have to confess I would rather have precision milled carbon steel or stainless parts in the action. If it was good enough for grandpan's guns, it's good enough for me.

Don't much care for polycarbonate frames, either, but I know most of them work out just fine.

 

[msinc]

Most guys equate the differences of MIM vs. forged to the automoblie industry...back in the hot rod days of the 60's and early 70's the performance cars sported a forged steel crankshaft instead of the usual cast iron crank found in the stock engines. Since forged car parts are more valuble and cost more it must be that a forged gun part has to beat a MIM one {makes sense to most guys.} Both methods have their good and bad. I have seen plenty of cracked and wrung off forged steel crankshafts in my 16 year previous career as an automotive machinist so forged steel is not a cure all. Since forged parts are hot stamped metal they do have somewhat of an "alignment" of the molecules and kind of take on a grain all going the same direction. In many cases that gives the part the strength it needs to last. In example, connecting rods in engines have been forged steel for a very long time, even in stock non-performance type engines. MIM on the other hand is very fine atomized metal "powder" that is heated and pressed into shape. This has several advantages...the crystalline structure of the molecules dampen and cancel out vibration and its associated fatigue so the service life can be much longer. It is easier to MIM form much harder alloys than it is to forge and then machine so you can get a much longer wearing part. How long do you want it to wear??? Just add some tungsten carbide dust. I think alot of guys see a broken MIM part at some point and note that the appearance looks like a very clean sudden break, as if the part just let go and didn't even try to hang on; as opposed to a forging that often cracks in a small area and continues to work for a while until it finally gives in.

 

[Mike_Dee]

MIM parts don't have the tensile strength of machined steel parts.

 

[carl3989]

Nothing wrong with MIM parts other than the looks. If they could just make them look as good as the forged parts with their beautiful case hardened colors.

 

[valkyriekl]

So why didn't S&W just rivet MIM firing pins into MIM hammers? Why the complete transition to frame mounted firing pins across the entire revolver lineup?

I think the answer is that the hammer mounted firing pins won't pass the drop tests some states, CA to be sure, require. That seems like a good idea so that they can continue selling their guns. Don

My take on the reason frame mounted firing pins (FMFPs) were used rather than hammer-noses were that FMFPs were already used for the rimfire guns - much simpler to use the same parts across the entire line of products* (the hammer noses were different shapes between J, K, L, and N-frames).

I believe it's easier to put a firing pin into a frame than it is to put one into a hammer, and then have to make sure the tolerances are such to allow that hammer assembly to be used in a frame.

I also believe that having a FMFP also reduces the likelihood that a firing pin hole could get elongated or misshaped by repeated cycles of the action.

*The MIM K- and L-frame hammers are also the same part. I *think* the MIM N- and Z-frame (Governor) hammers are the same part (I know for sure the hand is the same between the N- and Z-frame). The K/L/N sears and stirrups were and are all the same part; the K/L/N trigger rebound slides and trigger assemblies were all the same, along with their springs, the mainsprings, etc. So having similar parts across the line helps keep costs down.

 

[slabside2]

Yes S+W started using MIM parts to cut the cost down...... Yea for them. They sure as hell don't pass the saving on to us. Let's face it forged parts are better. You can fool yourself into thinking there the same or better but there not. If they are the same or better why don't they use them in there more expensive P.C. guns?

 

[DonD]

Let's face it forged parts are better. You can fool yourself into thinking there the same or better but there not. If they are the same or better why don't they use them in there more expensive P.C. guns?

You have an advanced materials science degree? If you don't you're probably not qualified to state that with conviction.

Ever consider that S&W might put forged parts in place of MIM on PC models just to satisfy the PERCEPTION that forged is better than MIM to please the part of their audience that hates change?? Don

 

[DonD]

My take on the reason frame mounted firing pins (FMFPs) were used rather than hammer-noses were that FMFPs were already used for the rimfire guns - much simpler to use the same parts across the entire line of products* (the hammer noses were different shapes between J, K, L, and N-frames).

I had a conversation today with a S&W firearms engineer I know. I brought up the issue of frame mounted firing pins saying one of the big reasons for using them was passing drop tests. He said yes.

Regarding 2-piece barrels, another feature many dislike. Again, it's there to reduce stress on the barrel and the frame interface. Good reasons for both design features. Don

 

[slabside2]

You have an advanced materials science degree? If you don't you're probably not qualified to state that with conviction.

Ever consider that S&W might put forged parts in place of MIM on PC models just to satisfy the PERCEPTION that forged is better than MIM to please the part of their audience that hates change?? Don

Yo Don ease up a little. I didn't say I hated MIM parts I even own a couple guns with them. It's just one man opinion on the subject. If you want to keep drinking the cool aid smith & wesson is poring thats up to you. When they go from MIM to plastic lets see if you feel the same way. Oh by the way about the plastic thing I also own a S + W M+P shield and  a Glock love them both. 
Take care.
Mike  

 

[rbmcmjr]

I had a conversation today with a S&W firearms engineer I know. I brought up the issue of frame mounted firing pins saying one of the big reasons for using them was passing drop tests. He said yes.

That doesn't make sense to me. The frame-mounted pin is susceptible to inertial movement (gun stops, pin continues forward). The hammer mounted one isn't because the hammer block prevents it.

Unless I misunderstand the lockwork...?

 

[DonD]

That doesn't make sense to me. The frame-mounted pin is susceptible to inertial movement (gun stops, pin continues forward). The hammer mounted one isn't because the hammer block prevents it.

Unless I misunderstand the lockwork...?

There are LOTS of people on this forum with far more knowledge of the internals of S&W revolvers than I have. In the case of the frame mounted firing pins, I'm just reporting what the engineer said. He was a big player in the development of the Model 500. Don

 

[SweetMK]

That doesn't make sense to me. The frame-mounted pin is susceptible to inertial movement (gun stops, pin continues forward). The hammer mounted one isn't because the hammer block prevents it.

Unless I misunderstand the lockwork...?

We need a physics professor to chime in to answer this one.

The frame mounted pin is so small, it has a tiny amount of mass.

For that tiny mass to be effected by velocity, the gun would need a WHOLE LOT of velocity.

At that velocity, slowing down fast enough to make the firing pin move enough to set off a round in the chamber, I would bet the gun becomes the projectile doing the damage,

forget about the bullet!!

IMHO

 

[brucev]

Tradition and emotion are ... tradition and emotion. The fact is that the FMFP and MIM parts are an improvement. We don't have to like it. But there it is. It's not unlike the outrage of those who so adored the 1903 rifle. Yes the early rifles were made beyond the level of quality required for a service rifle. They were beautiful. But, the realities of WWI demonstrated the weaknesses of the design. In WWII, Remington improved the design with the 1903-A3. Purist hated it for being not as finely finished, etc. But there was no denying that it was an improvement especially in stocking, sighting and use of a one-piece trigger guard/magazine. The only reason anyone ever made parts by forging/milling was because the ability to make MIM parts did not exist. Colt once made SSA's w/ HMFP's. Ruger came along and took an idea from H&R and produced a better SA revolver, with a FMFP. It has proved outstandingly successful. One other thought about MIM... I may be wrong, but if I remember correctly, many of the critical internal engine parts in modern Jet motors are made by the MIM process. How many millions of people daily fly in planes which depend on such MIM parts to keep them all in the air?

 

[Gamecock]

Tradition and emotion are ... tradition and emotion. The fact is that the FMFP and MIM parts are an improvement. We don't have to like it. But there it is. It's not unlike the outrage of those who so adored the 1903 rifle. Yes the early rifles were made beyond the level of quality required for a service rifle. They were beautiful. But, the realities of WWI demonstrated the weaknesses of the design. In WWII, Remington improved the design with the 1903-A3. Purist hated it for being not as finely finished, etc. But there was no denying that it was an improvement especially in stocking, sighting and use of a one-piece trigger guard/magazine. The only reason anyone ever made parts by forging/milling was because the ability to make MIM parts did not exist. Colt once made SSA's w/ HMFP's. Ruger came along and took an idea from H&R and produced a better SA revolver, with a FMFP. It has proved outstandingly successful. One other thought about MIM... I may be wrong, but if I remember correctly, many of the critical internal engine parts in modern Jet motors are made by the MIM process. How many millions of people daily fly in planes which depend on such MIM parts to keep them all in the air?

What a pile of false dichotomy. The 1903-A3 was better, so MIM is better ?!?!

 

[dswancutt]

What a pile of false dichotomy. The 1903-A3 was better, so MIM is better ?!?!

No, his point was that the 03A3 where often looked down upon because the barrel bands, butt plate, trigger guard, and rear sight where stamped, not milled, and therefore of "lesser quality". Only in the last ten years or so have the 03A3's started to gain in popularity, especially with the rise in CMP bolt actions matches, because they are easier to shoot accurately, mainly in the rapid fire stage.
Reason for not liking MIM parts have been how it looks or how the gun sounds when it is cocked. Almost everyone sheepishly admits that the action is smoother than forged.
ALL of my S&W revolvers are pre MIM and IL. As of yet, I haven't seen a new revolver that I have to have. The IL turns me off more than the MIM.

 

[CoMF]

I'll be one of the first people to admit I hate them purely for the aesthetics. Frankly, I just don't think they look as nice as forged case hardened parts, and I can't stand hollowed out or scalloped triggers and hammers with sprue marks. If they were cosmetically identical to their older forged counterparts, I'd probably pay them no heed.

FWIW, back when I wanted to get rid of my Glock because it was just "too much gun," I -almost- ordered a brand new, NIL 442 Centennial. Seeing a circa '71 Chief's Special in my LGS's display case for a comparable price made me rethink that decision.

Buy whatever you want, but I still opine that traditional S&W revolvers better fit the description of "an elegant weapon for a more civilized age."

 

[Agent Smith]

Vote for MIM

I for one feel that the MIM parts are a huge step up, I only own one gun with MIM parts, but they do fit much better than my older models. And, Yes I have had the lock works out of all my other guns at one time or another. One of the biggest things I noticed is how much smoother the MIM rebound spring block is compared to the forged part guns. A number of the blocks in the forged guns are really rough, almost like they didn't even bother to try and smooth them out.

 

[slabside2]

I'll be one of the first people to admit I hate them purely for the aesthetics. Frankly, I just don't think they look as nice as forged case hardened parts, and I can't stand hollowed out or scalloped triggers and hammers with sprue marks. If they were cosmetically identical to their older forged counterparts, I'd probably pay them no heed.

FWIW, back when I wanted to get rid of my Glock because it was just "too much gun," I -almost- ordered a brand new, NIL 442 Centennial. Seeing a circa '71 Chief's Special in my LGS's display case for a comparable pric





made me rethink that decision.

Buy whatever you want, but I still opine that traditional S&W revolvers better fit the description of "an elegant weapon for a more civilized age."

+1 Well said.

 

[brucev]

What a pile of false dichotomy. The 1903-A3 was better, so MIM is better ?!?!

Sir, you are of course welcome to your own opinion which doubtlessly reflects your own experience. The opinion I expressed was not formed in a vacuum. It and the comparison I made reflect my own personal experience in owning and shooting.

I have been shooting 03-A3 and 03 rifles for 30 years... about the same amount of time as I've been shooting S&W revolvers. One of my favorite rifles for use in vintage military rifle matches is a Remington made 03 (1942) arsenal rebuilt (RA-P) sometime after 1944. It averages 96.9 for 10 shot strings fired slow fire prone. My Remington and Smith Corona 03-A3's with the same load will produce equal scores. When it comes time to go into the woods on a deer hunt, I carry the 03-A3. It is simply a better design for hitting game at any distance.

I currently own a few S&W revolvers. Yesterday was my 56th birthday. I took a number of them to the range and had a nice time shooting them. If I had had any .44 Special ammunition, I'd have also carried my 21-4 Thunder Ranch revolver. It has the MIM parts and the IL. The IL has not been a problem to me. As soon as I get the time I will remove the IL and plug the hole with one of the little items sold for that purpose. If forged color cased parts were available to replace the MIM OEM parts I would not buy them. Why? The 21-4 w/ the MIM parts is simply in every respect excellent as to fit, finish as well as the quality of the DA and SA trigger pull.

I have S&W revolvers that were produced from 1968 through 1988. And I have the 21-4. I am not sure when it was produced. Dry-firing my N-frame revolvers in comparison with the 21-4 I am not able to discern difference in the quality of the SA trigger pulls. The DA on the 21-4 is superb, as good as my 4" 28-2 and 625-2 and (I know this is subjective) possibly better than my 6" 28-2. I have two K-frames... a 15-3 and a 4" 66-2. The 15 has the best DA/SA of any revolver I own. The 66 is almost as good. Maybe if I handled many many revolvers with the MIM parts, I might discern some differences. My opinion is formed only on my own experience w/ the 21-4 that I own. It is not the same as the original 21, but I don't have and never will have the budget to afford a original production 21. This 21-4 is about all anyone could want in a revolver. It is exceptionally accurate, the SA and DA trigger pulls are excellent and the fit/finish are startling.

 

[99savage308]

I have to say something 'bout this MIM stuff.

Milled,forged,cast and mim. What is the fuss 'bout ?

Who gives a chit? I sounds like a lot of so called collecter type ****.

 

[ladder13]

I have to say something 'bout this MIM stuff.

Milled,forged,cast and mim. What is the fuss 'bout ?

Who gives a chit? I sounds like a lot of so called collecter type ****.

So how do you really feel?

 

[DonD]

People have been bitching for years about Ruger's investment casting saying it's "SO" inferior to forgings but Ruger's SuperRedhawk in .454 where they use an exotic alloy called Carpinter takes SERIOUS pressures routinely.

Apparently Ruger, which has a large reputation for rugged guns, finds that "inferior" investment casting works just fine. Don

 

[Gamecock]

The 1903-A3 was a great rifle.

Ruger's investment cast guns are rugged.

Ipso facto, MIM is good. You guys are weirding me out.

 

[dswancutt]

The 1903-A3 was a great rifle.

Ruger's investment cast guns are rugged.

Ipso facto, MIM is good. You guys are weirding me out.

Please show us PROOF that MIM is bad. A forged part is only as good as the bar stock it is made from. I am pretty sure that a MIM metal is much more pure than any bar stock. And, if it is such an inferior process, why are turbine blades made using the MIM process.

It would be interesting to compare the reject rates between the forged parts and MIM pre and post machining.

 

[ltxi]

But, as noted, an ugly looking and often cheap feeling gun is still an ugly looking, cheap feeling gun no matter what it costs nor how well it works. It's called an appliance.

Many of us gun folk prize form as well as function.

 

[Gamecock]

Please show us PROOF that MIM is bad.

Not my job, man.