In defense of MIM

[ugaarguy]

I find it hypocritical that many in the firearms community will talk about how great Kimber pistols are, and how strong Ruger pistol frames are. Then they turn around and tell you that MIM is an abomination and how all firearms should be forged or machined from solid bar stock... and then be blued with ivory or hardwood grips... "the way God intended." Kimber has a reputation for making great pitols; they claim they brought MIM technology the firearms industry. Ruger's now legendarily strong frames are cast; when they started casting frames everyone said it was horrible and that they could never be as strong as a forged frame. Everyone freaked out when Glocks hit the US market; how in the world could a <gasp> plastic framed pistol be reliable or durable? Well 20 years, over 70% of the US LE market, and a blatant copy by S&W later they've proven themselves. I'm just asking everyone to accept MIM for what it is - a new technology - not a herecy, nor a miracle. There will always be naysayers who refuse to change. I'll take quality however it comes. I own Glocks, I own an old S&W M&P revolver, I'm saving money for a 1911 while I try to figure out which one I want, and I even enjoy shooting SA revolvers. I'm not trying to stir up a controversy; I've just gotten tired of folks bashing MIM when Kimber and others have proven it works when done properly. Just like any other manufacturing technique it all depends on good execution and quality control.

Donning my flame proof suit now...

 

[EddieCoyle]

Here we go....


MIM is great - for some parts. Investment casting is great - for some parts. Machining, forging, stamping, PM, etc. are all the perfect process in the right applications.

On the other hand, you wouldn't want a gun with a MIM extractor, cast barrel, machined magazine, stamped hammer, and PM magazine spring.

A lot of the MIM bashing is a result of some companies using MIM parts where they did not belong. For example, Kimber used MIM for the extractor. (EDIT: My bad, it was Colt, not Kimber)

You will get a quality gun when the design is sound, the materials are correct, the fit and finish are well executed, and the proper processes are used for the proper parts.

 

[Geno]

"Proven"? Not Quite.

Proven isn't quite there. Have they shown? Sure. Does their success "suggest"? Sure. Does it "prove". No.

There is one simple test for this. A randomly sampled set of pistols, 30 in MIM and 30 in bar. Fire them until they break. Enter the data into SPSS or Minitab and test the null hypothesis that there is no statistically significant difference between group mean scores of MIM V. bar pistols' durability.

For my part I simply hate that ugly dimple that MIM leaves, or more accurately stated that Kimber, et. al. leave after the process. Furthermore, while MIM does work, it is known that bar is stronger, more resilient. All of this aside, I don't see any company handing out 30 to 60 pistols and all of the ammunition for this test.

As a "cheaper" alternative, they can simply offer a lifetime warranty. If their product is so great, that solves the concerns, right? Mostly. We still need to be concerned for CCW carry. Until then, I's bet my next cup of joe that most people still prefer forged and bar. Why? Because it's their dollar and their life.

This is going to be an interesting thread. Thanks for beginning it.

Doc2005

 

[lawson4]

MIM is the right choice for certain applications.
It's mentioned that "...you wouldn't want a gun with a MIM extractor,...", however, many extractors are MIM'ed. It depends on the design of the part, as well as the function, as to whether bar, cast, forged, etc, is the best choice.
Some hammers are MIM'ed, then machined and you would think they came from bar.
The "dimple" left behind is either from poor design or the designer thouhgt the cosmetics were unimportant; it probably doesn't affect function.
The metals and methods of today's MIM parts make them as strong and reliable as machined bar in the right application.

lawson4

 

[xring44]

I have been one who screamed loudest in the past, a shineing example would be the pre 64 model 70 winchester rifles vs. the post rifles. The early post 64 rifles were a POS. Cost of production was driveing the price of the product out of reach of many shooters. I see the mim parts the same way, cost of manufacturing all machined parts would be excessive for most consumers.
On purchasing a new S&W, I strip it and stone all parts that are feasible. I can honestly tell no difference in the slickness of these actions and the pre-mim actions. No complaints here.

 

[Jim Watson]

Good quality.
Done properly.
Certain applications.

There's the rub, MIM is being used as a cost cutting approach and we are not getting the certified aircraft grade material in parts designed to be molded instead of milled that they use for their advertising.
Sears in bulk for $.50 wholesale is not a confidence builder.

The paying customers got to do the beta testing and the warranty clerk got to do the final engineering as they figured out how to use the stuff.
Kimber put out a bunch of guns early on with slide stops that did not engage reliably, probably because they had not figured the shrinkage of the complicated shape correctly. A bunch because molds are expensive and they were reluctant to replace one until it was abundantly clear that it was not right. Then they overcompensated and furnished slidestops that engaged prematurely. At least those could be filed to fit like the common cast part.

No doubt one of these days we will hear advertising - "All parts traditional MIM, none of that cheap AMA (Artificial Metal Alloy) junk."

 

[Dave Markowitz]

Comparing MIM to Ruger's investment casting process is not an apples to apples comparison, it's apples to oranges. They are different and so far, the end result is different. Further, Ruger's guns are designed with investment cast production in mind, whereas MIM has heretofore usually been used to produce parts that were designed to be made from forged or milled steel.

 

[Tropical Z]

I'll pass on Kimber's for sure and MIM if at all possible.

 

[Ken Rainey]

IIRC, It was Colt who used an MIM extractor and found it wasn't acceptable. Kimber discarded the idea and went with barstock.

 

[Socrates]

I've got two Kimbers, a Custom II, and a Kimber Ultra Carry II.

I had a couple parts break, and, I bought Ed Brown, and Wilson forged parts, for both guns, and haven't looked back.

Wasn't all that expensive, and, the Kimber frame and main parts are fine.
Guns drive tacks...in particular, the Custom II..

S

 

[MachIVshooter]

When done properly, both investment casting and MIM are nearly as strong as forging and far superior to stamping or milling out of mild steel billets.

We would all love to own guns milled from forged tool steel, but t he cost would be astronomical.

Gun makers face the same challenges as many other industries. People want more for less. Look at what has happened to automobiles. If you wanted a brand new Chevy sedan with all the modern bells and whistles and the same attention to detail and quality as a '55 Bel, you'd be paying better than twice as much. Instead, people want all the goodies at minimal cost so the automakers use lots of plastic or stamped parts, cheap clips instead of machine screws, etc. What you end up with is cars that fall apart in less than a decade. Be glad that guns have not fallen that far.

 

[45auto]

Consumers see broken MIM parts on the internet or experience them in their gun.

If they didn't break, no one would care how they were made. The real question is how often and what percentage "snap"...don't know.

But, if I just spent $750-$900 on a production 1911, I wouldn't be amused at a broken part. Particulary on a non-stress part like a thumb safety, mag catch, etc.

I'm not against MIM, just save a little less and do it right!

 

[EddieCoyle]

MIM does not equal inferior. MIM is a relatively new manufacturing technology (1980's) and the process is quite complex.

It was inevitable that manufacturers would learn on the fly, and some quality problems occurred. MIM parts are better now than they were five years ago, and are likely to improve further. MIM parts can be made better and stronger than forged parts at a fraction of the cost.

I wouldn't buy some older guns with MIM parts. However in the future I won't let the fact that a gun has some MIM components prevent me from buying it.

 

[Kevinch]

another MIM discussion......

MIM can probably still be considered an emerging technology, a method by which intricate parts can be produced close to finished shape without machining ("near-net" is the industry term), requiring only a minimum amount of machining to bring into final close tolerance specifications. It is more economical than machining or wire EDM from bar or plate stock. If you think basic Kimber is expensive now, I think we'd shudder at what it would cost without inclusion of MIM parts. Same with CNC machining. When done correctly & used in the proper application, MIM will perform as well as a wrought product.

My employer doesn't do MIM yet, but we do press & sinter metal powder - primarily, tungsten alloys (~95% pure tungsten). Had Ruger as a customer once but lost them - I'm told they went to MIM. While a press & sinter process is more cost efficient than machining from wrought material, MIM can be more efficient than P&S in certain applications.

Whether you like it or not - it's here to stay - just like plastic bumpers & painted grills.....

 

[ghost squire]

Look... when we start making entire airplanes and industrial machinery out of MIM/sintered/cast parts then I'll take a look at buying a gun made of them. Until forgings cease to exist its clear that they are tougher. Ruger beefs up the critical locations in its guns.

What are these proper applications that MIM parts can be used in?

 

[ArmedBear]

I think that the extractor on an 870 Express is a MIM part.

Now a shotgun shell is rimmed, the extractor is large, and it does chew up the rims of some shells a bit. But the extractor works fine, and it lasts for a long time.

But I've had machined parts break -- steel parts, just break in half like they were made out of clay.

It's hard to make a broad generalization about much. There is such thing as bad machining, bad forging, and bad steel. If you factor cost in, you might actually prefer to get a MIM part at a certain price point.

Kimber, of course, is priced at the higher end, so you'd expect a machined extractor.

 

['Card]

...designed with investment cast production in mind, whereas MIM has heretofore usually been used to produce parts that were designed to be made from forged or milled steel.

Excellent point. That's the most intelligent thing that's been said in this thread thus far.

 

[paul45]

Kimber has a reputation for making great pitols;

They do ?.....You must not get out much...

 

[Master Blaster]

Let me take a wild guess and say you dont own any kimbers..

I do and with about 10,000 rounds on one and 0 problems, it still looks and shoots like new, and shows virtually no wear to the slide frame barrel bushing fit. I think they do make a great pistol.

 

[MadMercS55]

In my experiences Kimbers can be very hit or miss. If you get a good one, go with it. But for awhile there it seemed there were alot of varying problems. Guys at my range suffered broke thumb safeties, ALOT of extractor issues, from breaking off, to proper tension troubles.

 

[JohnKSa]

...when we start making entire airplanes and industrial machinery out of ... cast parts then I'll take a look at buying a gun made of them. Until forgings cease to exist its clear that they are tougher. Ruger beefs up the critical locations in its guns.

Ruger casts turbines for jet engines--probably one of the most critical parts in terms of strength and quality control for aircraft. Furthermore, there is evidence that in certain applications, cast parts are actually superior to forgings.

I'm not saying that casting will ever eliminate forgings, but it's a mistake to assume that cast parts are always inferior to forged parts. It's just not true.

 

[RON in PA]

I won't make any comments about MIM parts in 1911s, but do know that one reason that Smith&Wesson went to MIM hammers and triggers in their revolvers was that they determined that these MIM parts stood up and were cost effective in the lifetime warranty they provide. They aren't as pretty when it comes to the appearence of the color casehardening, but they work fine in my experience.

 

[Kevinch]

Look... when we start making entire airplanes and industrial machinery out of MIM/sintered/cast parts then I'll take a look at buying a gun made of them.

That sounds good - but I wonder if that's what the Wright brothers would have said about airplanes made out of aluminum instead of wood & cotton ......

 

[gearbox]

I'm biased against MIM simply because I was into guitars before MIM came about. In the land of guitars, a MIM Fender Stratocaster means "Made in Mexico"
But I do admit to owning a MIM strat alongside an AmStd.

 

[EddieCoyle]

Look... when we start making entire airplanes and industrial machinery out of MIM/sintered/cast parts then I'll take a look at buying a gun made of them. Until forgings cease to exist its clear that they are tougher. Ruger beefs up the critical locations in its guns.

In the mean time, keep flying in those forged airplanes.