MIM Gun Parts?

[Joshua M. Smith]

Hello,

I learned about MIM, casting, forging, etc in college a while back.

MIM and casting always seemed to have about the same weaknesses in my mind.

After ordering and installing this MIM safety on my 1911, I got to taking a hard look on what's NOT forged in modern firearms.

Turns out, almost everything in non-custom guns is MIM. Armscor uses MIM frames (Armscor makes these for STI, RIA, and until recently, Charles Daly). Kimber is pretty much all MIM. Wilson uses MIM.

Remingtons have a lion's share of MIM parts and the company owns its own MIM plant.

Smith and Wesson revolvers are using MIM parts internally.

Colt uses MIM.

Ruger, if I read right, uses cast frames and slides with MIM internals.

They all hold up well. Yet people hate MIM.

Why? And what are your experiences with MIM?

I personally had ONE MIM part ever break on me. It was a joint on an ambi safety from first year Charles Daly 1911 production, and it had an obvious flaw. In other words, it was a goofed step in the process, not the process itself.

So, what are your feelings on MIM? Are they functional? Have they made all our firearms into crap?

Josh <><

 

[jaydubya]

My S&W 637 and 686+ both have them. I've fired several thousand rounds through each with no problems. I too am puzzled by the hatred -- no other word is strong enough -- that MIM parts have created.
Cordially, Jack

 

[VHinch]

MIM is good at what it does. It makes the production costs low enough to make lower priced guns possible. Your Charles Daly wouldn't have cost $400 new if it wasn't full of MIM parts. That makes a lot of guns, 1911's in particular, available in price points where more people can afford them.

I take them for what they are. I don't have a particular hatred of them, and I have plenty of guns that utilize MIM parts. The guns I carry however, do not use MIM parts. I understand that making that choice is going to cost me more, and I am willing to pay for the difference.

 

[Fat Boy]

I wasn't aware Ruger used MIM parts...is there a way to learn exactly what guns use MIM parts, and what parts they are?

 

[Joshua M. Smith]

I've seen some short lists on this lil' 'net crusade I'm on, but everyone's list seems to be different on who uses them.

As far as I can tell, only Nighthawk and (maybe) Brown don't use them.

Nighthawk states this specifically.

Josh <><

 

[davepool]

Okay, i have to ask the stupid question....what does MIM mean?

 

[Gun Slinger]

It is not a stupid question, man. MIM stands for Metal Injection Molding.

Not a metallurgist, but in the conversations that I have had with the two that I do know personally, they indicate that the process is a well respected one and that done correctly, the parts produced are adequate for most uses that they are put to in firearms.

The problem is actually one of perception. I'll elaborate.

Fact is, most equate the process as being synonymous with "sintering", a process that produces parts that are by comparison far weaker than investment cast parts due to the initial size of the metal particles used in that process. MIM uses metal particulates several orders of magnitude (100x-1000x) smaller than sintering and produces a higher density (read: less voids which serve as internal starting points for stress induced failures) and therefore much stronger, end-product.

When it comes right down to it, wrought/forged parts, MIM and sintered components can all fail and sometimes do, even when they are properly produced and all have their place in the modern manufacturing process.

If you've misgivings about them for whatever reason or just plain old don't like them, then do some research and find a product that suits your tastes. Just be prepared to spend a little (or a lot) more for what you want.

I, for one, don't worry about it to begin with and if I absolutely don't want a product that uses the technology, it is relatively easy to correct the "issue" or find a product that doesn't utilize the MIM process.

Regards,

 

[davepool]

Thanks, makes a lot more sense to me now that you've explained the process...and i agree, they should function well if the process is done correctly

 

[VHinch]

As far as I can tell, only Nighthawk and (maybe) Brown don't use them.

Those 2 are correct, as well as Les Baer. The higher end Dan Wessons are MIM free as well if I am not mistaken. You also won't find any MIM in the old Commercial Colts, which is one reason I prefer them and my Baer TRS for EDC.

 

[mtngunr]

MIM is still not as strong as machined barstock or machined forging....but, hey, we're only talking about something you might depend on to save your life.

MIM today is denser than earlier versions that had smiths refusing to try action jobs on them.

Colt has gotten away from MIM to a large degree, and never were they at the level of many current makers....and some of the brands mentioned here as MIM/cast free might suprise owners. Offhand, and without my list, Colt does NOT use MIM or cast for extractors, firing pins, hammers (aside from the 01911 and 01918) slide stops, bushings, frames, slides, plugs, firing pin stops, barrels, links, pins, plunger tubes....they briefly used MIM extractors which had a horrible failure rate, and have stepped away from cast plunger tubes due to loosening problems....sear/disconnector MIM, MSH cast, thumb safety MIM, mag latch MIM.....forgive me if I don't list more....

Personally have no problem aside from aesthetics on MIM non-stressed small parts, but aesthetics are a large part of what determines what guns I buy.....I won't buy a new Smith because I know what the parts inside look like, with part lines, sprues, rough finish, etc hiding in there on near every part today....why buy that when I can buy an older nicer-made gun of superior materials for LESS money?

 

[Just Jim]

I believe that MIM parts started in 1989, so if you want a non mim gun then buy before then.

jj

 

[denfoote]

Just for S's and giggles, I went into my Midway catalog and designed a 1911 using all non MIM parts.
By the time I was done, I was over $1000!!!!
Forged parts are nice, but they are way expensive!!

 

[Charles Daly]

Joshua,
Where did you hear that Armscor 1911 frames are MIM? From my understanding they have always been cast.

Just curious,
Michael

 

[mljdeckard]

I have my suspicions, which are really just that.

For many years, 1911s came pretty much in two flavors. G.I. styles and high end custom guns. Then, in the mid 90s, Kimber shoved into the 'semi-custom' market. They showed that a hand-fitted slide does not in fact cost several hundred dollars to produce. All of a sudden, there was a way to have a nice, tight, reliable 1911 without spending over $1-2000 to get it. The 1911 market exploded, and other manufacturers followed suit.

Of course, there still existed 1911 snobs, who had been buying Wilsons, Baers, etc, for years. They were suddenly faced with the stark question, "What is it your $2000 'custom gun' can do that the 'semi'custom' gun can't?" A conundrum indeed. A couple of years ago, I shot a Nighthawk at Impact. Wow. Tight. Gorgeous. Those machined aluminum grips were VERY nice. But it was priced at over $2000 MORE than my Kimber. I was reminded of Vincent Vega in Pulp Fiction. "Wow. That's great. That's the best milkshake I've ever tasted. But it ain't worth $5."

If MIM parts are doomed to fail, all mine must be defective indeed. I'm north of 10k rounds in my Kimber, and I don't even know how many .22s I've shot with the conversion kit, and it is by far the most reliable pistol of any caliber, configuration, or manufacture I have ever owned. It's a pity my sons will never know this, because I think I am going to be buried with it. Other manufacturers I have carried, and had many problems with, (S&W Sigma, Beretta, Tarus, Ruger, Para Ordnance,) would LOVE to make pistols this terrible.

Replace the MIM parts? This is the best pistol I've ever used, I'm not changing a thing. I added night sights, Hogue finger-grips, dropped the full-length guide rod, otherwise it's bone stock. It's my only carry gun, I take it hunting, I would take it to war tomorrow if my command would look the other way. (Which they won't.)

 

[Golden Hound]

Hahaha, I was reading this the whole time assuming that MIM meant "Made in Mexico," since that's the terminology for Fender guitars. You learn something new every day.

 

[shootinstudent]

For many years, 1911s came pretty much in two flavors. G.I. styles and high end custom guns. Then, in the mid 90s, Kimber shoved into the 'semi-custom' market. They showed that a hand-fitted slide does not in fact cost several hundred dollars to produce. All of a sudden, there was a way to have a nice, tight, reliable 1911 without spending over $1-2000 to get it. The 1911 market exploded, and other manufacturers followed suit.

You have a lot better luck with the tight frame/slide fit of these new semi-custom guns than I have.

I've seen stock Colts run with zero failures out of the box.

I've seen two SW1911's, one Springfield 1911A1 stainless, and two kimbers go from purchase to range....all had FTF's out of the box.

 

[Joshua M. Smith]

Where did you hear that Armscor 1911 frames are MIM? From my understanding they have always been cast.

Michael,

There are several people stating this via the Internet. Just run a Google search.

Then again, it may be misinformation that someone posted and the rest just ran with.

I don't remember the source, but I do know that I heard it stated that the slide was forged or cast (don't remember which) and the frame, MIM.

Again, right now I can't confirm it. Mainly 'cause I need to get to bed.

I'll look around some more tomorrow.

Josh <><

 

[VHinch]

I'm pretty certain that the all the Armscor frames are cast. Not saying they don't exist, but I have never even heard of an MIM frame on a 1911, and running a google search on it only brings up your threads on this topic.

I have seen instances where people don't understand that casting and MIM are not the same process, perhaps that's where this one started?

 

[Shear_stress]

I have seen instances where people don't understand that casting and MIM are not the same process, perhaps that's where this one started?

Exactly. Seems like there is too much internet rumor mongering and speculation by people who don't know the difference between MIM, investment casting, forging, pressing, machining (which can be used to craft parts straight from billet or used as a finishing operation for cast, pressed, or forged parts), etc to have an informed debate. All forms of manufacturing have strengths and limitations and are all capable of producing high or low quality parts.

 

[Cesiumsponge]

A lot of people seem to fear new technology. It might be ignorance, or the "back in my day" mentality.

There are still revolver people that scoff at autoloaders. 1911 guys that scoff at Glocks, Glock guys that scoff at Springfield XDs. People that don't like magnified optics and swear real shooters use irons. People that disdain tritium inserts.

The same thing applies when new manufacturing processes have neat names that might be bled into their marketing campaign. Then you got people that claim handmade is better than a CNC center that can hold tolerances of 0.0001". People that claim this type of barrel rifling is better than that type. People that claim stainless is inferior to blued metal. That castings suck, or MIM sucks, or that forging is better than solid billet, or vise versa. That newfangled coatings like gunkote and ceramics are fads and real guns use a hot blue.


If all these people had their way, we'd still be using technology from the 1800's hand filing everything without interchangeability or mass production.

MIM is just another manufacturing process that lends well to firearms manufacturing on a large scale (since initial investments for the forms aren't cheap), but there will always be people resistant to change who will dismiss it as something inferior in their mind. Such is the way of the world.

 

[rcmodel]

Ruger uses Investment Casting, not MIM Metal Injection Molding.

As a matter of fact, they have a large IC plant / sister company in Prescott that makes parts for many major firearms manufactures as well as aerospace, and automotive industries.
http://www.ruger-firearms.com/Casting/index.html

Don't confuse Investment Casting with oldtime "cast iron", or MIM and such.

It's not even close to the same thing, or strength!

rcmodel

 

[cktad]

From 1911.org/Armscor/RIA forum:
Armscor/RIA MIM Parts -
slide stop
plunger tube
sear
disconnector
ejector

Frame is investment cast.
Slide is milled out of extrude stock bar (with a cross-section similar to slide).
Barrel is AISI 4140 grade round bar.

 

[Ala Dan]

MIM Parts

Originally posted by: Joshua M. Smith-

"As far as I can tell, only Nighthawk and (maybe) Brown
don't use them"

Well bud, the last time I checked- Les Baer doesn't use 'em either~!

 

[tekarra]

Gun Slinger,

Good post. Let me add a few points. The process to which you are referring is Powder Metallurgy. Sintering is the process of fusing the powder to make a solid part. Sintering liquefies only the surface of the powder particle to fuse it to the neighbouring particle. If the powder particles melt, the result will be a cast blob of metal. Powder metallurgy is the only process by which the density of a metal part can be made to vary. I guess this might be done with MIM as well, I am just not that familiar with MIM. Depending upon the use of the part, the size of the powder, the pressing force and the sintering time and temperature can be changed to affect the properties of the part. The finer the powder, the higher the pressing force and higher the sintering temperature, the more dense will be the part.

Good shooting.

 

[Old Fuff]

A lot of people seem to fear new technology. It might be ignorance, or the "back in my day" mentality.

Yup, that's the Old Fuff for you, elderly and dumb. Hardly knows anything. Simply rejects anything that's new out of total ignorence.

But then it might be noted that his experience spans some 60 years plus, with a lot of those working within the firearms industry. Somewhere in there he did learn the differences between various manufacturing methods, and observed that sometimes - just sometimes, manufacturers would turn to alternative ways to make things simply to save money without worrying about quality issues. Anything that would work, at least in the short run, was acceptable to the company bean-counters.

Now it is said that you can fool some people some of the time, and others all of the time, but you can't fool everybody all of the time. I think that applies to the idea that doing it cheaper is better. Occasionally that might be true, but in the meantime the Old Fuff, being stupid as he is, will continue to focus on guns made the old ways.

Anybody want to join me...?