MIM parts breakage Infant Mortality or Random?

[wally]

Lots of complaints about MIM parts around here.

So far, I've not had any MIM parts break. I did have a "quality" extractor in a Series 70 Colt break, but this was after many many many thousands of rounds in a gun I used to shoot IPSC with.

Statistically most parts fail early in the product life cycle -- so called infant mortality which is why manufacturers offer a warrenty to keep the customer reasonably happy, or very late in the life cycle -- wear out phase. This is called the "bathtub" failure cure in textbooks.

My failure in a machined metal part would probably be considered to be in the wear out phase or one of the low probablity random failures in the normal lifetime phase -- I though needing minor parts replacement after 10000 rounds was "normal" for a miltary contract 1911.

My question is how many have actually experience MIM parts breakage and if so was it low round count say less than 500-1000 rounds high round count >10000 or "random" after solid break in, but well before normal service life?

--wally.

 

[wally]

Details please. What Broke?

Particularly want to know if the gun was truely out of action from the breakage.

I know the collet bushings in the Series 70 Colts truely put the gun out of action when they broke. My broken Series 70 Colt extractor still let me single load a round in it and shake out the empty after the slide locked back -- managed to still get off enough shots to pass my CHL qualifer after mine broke -- Murphay's Law sure hit me circa 1995. Original collet bushing on my Series 70 is still doing fine.

--wally.

 

[bountyhunter]

I think Tuner has a box of broken extractors and/or safeties he uses as a boat anchor when he goes fishing.

 

[Correia]

I have two experiences. Neither with my own guns, but both from other shooters that occured in IDPA matches. Both were thumb safeties. The shelf broke off leaving just a jagged edge. Both were on very new guns.

With that said I still use a Kimber in competion, and carry one on a regular basis, with all of the MIM parts still inside. I'm not worried about it.

 

[1911Tuner]

MIM

MIM parts, when well-made can actually be pretty good. The
problem is that ya never know unless ya magnaflux it, and by the time
that's done, you could have upgraded the gun with real steel small parts
for less money, and put your mind at ease.

I've found that, if an part MIM is gonna turn loose, it'll do it early in the game. If it lasts beyond a couple thousand cycles, chances are it'll hold up
for years. I've got a mid-90s production Colt 1991A1 that has MIM
sear and disconnect that's never given a problem. By contrast, I have a late production NRM Colt that cracked the sear the first month...and know
of another one that a friend bought about the same time that's held up
for well past 10,000 rounds.

The only hitch in that gitalong is that a thumb safety is used so infrequently, that it may be a bad part, and won't show up until the
gun has been in service for years.

Upgrading the gun doesn't necessarily entail replacing all MIM parts. There
are some applications that MIM is well-suited for, and will last a long time even if the part is flawed. The mainspring housing is one such, but those
are generally castings these days. The grip safety is probably okay too, though Kimber has had some of those to break in the last 10-12 months.
never had a McCormick MIM slidestop to break or fail in any way...but it's still MIM.

Bottom line...If it holds up for 2500 rounds, chances are it'll hold up for 25,000. Life's a gamble...Roll the dice!

Luck!

Tuner

 

[grendelbane]

Mainspring housings should be easy for MIM. After all, look at the plastic mainspring housings.

Tuner, is there any reason grip safeties are made of steel in the first place? It looks like aluminum, plastic, or even die-cast zinc would do for this part. I have an early Lightweight Commander. The mainspring housing is alloy, but the grip safety is still steel. Looks like they would have made it of aluminum also. Course, I hadn't even been born then, so they couldn't ask my opinion.

 

[1911Tuner]

Metallurgy 101

Howdy grendelbane,

The grip safety probably could be made of something less durable
if not for one fly in the ointment. Impact stress.

When the 1911 cycles, the slide cocks the hammer forcefully. So much so, in fact, that the hammer flies past full-cock and strikes the grip safety tang, bounces off and hits the slide...which prevents it from slamming back down onto the sear. Neat, huh? Several things modify the amount of impact. Mainspring loading, recoil spring rate and loading, and even the slide to frame fit has a small bearing on how fast the slide recoils.

The grip safeties didn't need to be particulary hard...the original specs called for plain old unhardened 1018 cold-rolled steel...and about the only way to harden 1018 is by case-hardening. There's just not enough carbon in it, so it has to be introduced from another source, and the hardened part is thin...about .015 inch or less. Softer metals like die-cast zinc and aluminum alloy would be damaged pretty quickly by the hammer during the
slam-bang cycle of a .45 caliber 1911.

MIM is harder than 1018 by virtue of its recipe...but it's not as flexible. Brittle doesn't quite describe it either...so probably just saying it's not
as tough as 1018 is closer to the truth. 1018 steel will "give" a little, while most MIM won't. If it flexes, it'll probably break.

Investment casting is more flexible in application, and can be very tough and durable, as Ruger proved years ago...The trick is to keep a close eye on the quality and the process. The drawback is that it usually doesn't
allow for a highly polished surface finish like good, ordnance-grade steel.

Tool grade MIM...or as we used to call it...Powder Metallurgy...results in
very hard cutting tools that perform at heats and surface speeds which would ruin a conventional high-speed steel tool bit...but it doesn't fare well
with impact stresses incurred with interrupted or starting cuts. It has to be fed smoothly and slowly to begin the cut, and if it comes to a break in the surface, it has to be stopped and fed slowly onto the workpiece again. It will shatter like glass on even mild steel like 1018 unless the cut is smooth and uninterrupted by something like a groove or a slot.

Hope this helps,

Tuner

 

[Pythonman]

Thanks for the great informative post there Tuner, as usual you never fail to suprise with your knowledge and insight. Now I'm not nearly as worried about the MIM parts in my SA. Didn't know about the MIM parts inside the Colts were basically the same as the SA other than the slide stop. I guess it's just a MIM world now, everyones using it.

 

[grendelbane]

OK, so that's why all grip safeties I have seen have been steel, of one form or another. Kind of knocks one of my ideas in the head. As Will Rogers said, "It's not what you know that gets you, its what you know that ain't so!"

I guess I can do as George C. Nonte suggested, hollow it out a little. I would like to take a steel Gov't model, and make it as light as possible. I already have both an aluminum and a polymer mainspring housing. The grip safety always seemed to be overly clunky to me. Of course, when I wanted them heavy, that was just perfect.

Fortunately the traditional commander grip safety works with my hand, and will bite my friend. Best of both worlds.

 

[wally]

5 in 39 is about ~13% failure rate. IMHO this suggests a problem. Its not a showstopper since all failures reported so far have been in the break in period.
Definitely not a situation to be satisified with, but not as bad as many of the comments on these boards might suggest.

--wally.

 

[Ala Dan]

No MIM parts breakage!

Best Wishes,
Ala Dan, N.R.A. Life Member

 

[JohnKSa]

5 in 39 is about ~13% failure rate.

Well...

My guess is that there are a ton of THR posters who have no idea that there are MIM parts in their guns.

Also, these kind of polls are likely to get a much better response from folks with troubles than from folks with none.

For example: Out of 1,000 MIM users with no trouble only 5% might vote where as out of 5 MIM users with breakage 100% might vote--they're more motivated.

The real story that this poll tells is WHEN MIM breaks. Infant mortality seems to be the failure mode...

 

[1911Tuner]

Infant Mortality

JohnK said:

The real story that this poll tells is WHEN MIM breaks. Infant mortality seems to be the failure mode...

True. If the part doesn't break in the first 2500 rounds, it'll
likely last for 25,000...but don't count on it.

As for the "bathtub" breakage figures...There are too many
old pistols floating around with original parts intact for this to be a
reliable yardstick...high-mileage pistols. I've got parts that have worn pistols slap out...one after another...and they're still doin' yeoman service in other pistols. I just transfer'em to the next gun and keep on keepin' on.

MIM is fine for a range queen or a game player. Shoot'em 'til they break and replace the part.(s) When the stakes are higher, I want real steel
in the high-stress or critical areas. Murphy is everywhere, and If my
life depends on the gun, I refuse to hand the guy an engraved invitation.

Cheers!

Tuner

 

[RandyC]

Extractor snapped on my Kimber after maybe 2500 rounds. I actually didn't notice till I was cleaning the gun. That's been the only problem. My Colt is still cruising along with no problems.

 

[Ktulu]

I have two Kimbers. The .45 has 10k plus rounds and the 9mm has 5k plus and it's gaining on the .45 fast. No MIM parts broken, yet.

 

[fix]

I have been following the MIM issues for several years now and have stayed on the fence for the most part. I don't like the idea of MIM parts as a general rule, but don't bother replacing them automatically either. One of the things I can't help but notice is that the discussion invariably revolves around 1911s and how MIM parts are the spawn of satan and will make an otherwise reliable 1911 a POS. Let's talk about other pistols. How many non-1911 pattern pistols are chock full of MIM parts? Anybody have any info?

 

[45auto]

S&W uses MIM now.

Remington has used MIM for many years now and has a division that produces parts for different industries.
I don't know if that's good or bad because who knows what parts are MIM, cast, forged, etc, etc.
The 870 pump gun is known to be a very reliable, durable shotgun.
While the 1100 shotgun is known for it's parts breakage in the "clay target world"... it's legendary. Design, MIM problem or both...don't know!

Kimber was foolish for "marketing" the MIM process IMHO. When parts break, it reflects on the process which reflects on their product, at least on the internet.
What brand of gun do you think of when MIM is mentioned?


It would be interesting to know who uses what, but if I were the manufacturer I wouldn't be too anxious to let the information out.

 

[1911Tuner]

How to Tell

An MIM part is pretty easy to spot unless the surface was dressed or polished prior to finishing.

Look for a circular, square, or rectangular sprue mark or even indentation somewhere on the part. You may have to look closely. This may or may not be accompanied by a parting line, as is evident on castings. There may be more than one sprue mark, and there usually is on a larger part. The mark may appear to have a raised center portion, or even a small dot or line that resembles a string of glue in it.

As for trusting it...I don't...and no argument will change that, no matter how well prepared or technical it is. Seen too much to believe otherwise. I understand that machined steel parts can and do break too, but in my experience, the breakage is less likely and less frequent with machined barstock than with MIM or investment cast small parts. Larger, heavier parts, or those that don't bear shock loads generally do very well in MIM if the process is well-executed and of good quality materials. There are no guarantees. All parts are subject to fail...Using real steel on a part that is critical to function simply reduces the chances of the gun suddenly failing when one is having an UTYAIA experience. It's not a real issue in a game gun or recreational toy...It can be a serious issue if the game is real.

Bottom line...Life's a gamble. Roll the dice.

Luck!

Tuner

 

[NMshooter]

The slide stop on my Kimber (series 1) cracked somewhere around 20K rounds, replaced with Wilson bulletproof, approaching 35K but no other problems. What would I reasonably expect to replace next?

 

[Black Snowman]

So far no MIM breakage. I have a Delta Elite and I know at lest the seer is MIM. I've replaced some parts for the sake of show and I'm pretty much positive they are all MIM considering their price. If I ever CCW the gun I'll put the good steel parts back in.

I doesn't have alot of milage on it since I replaced the parts. Maybe 200 rounds. No idea how much use the gun had before I got my hands on it. I look forward to torure testing the cheap parts with a plethora of full power 10mm loads now that my trigger pull is much improved

Only have about 170 rounds loaded up right now. Need to hit the reloading bench before the weekend.

Other guns I suspect MIM parts in: Taurus 669 relvolver. It had work done on the trigger before I got it so I've never needed to open it up and check the internals.

Browing Buckmark 5.5 Target. Don't see why they wouldn't use MIM somewhere in the tigger group.

I'm guessing the Desert Eagle, CZ 75B and the Glock are all steel, or steel and plastic in the case of the Glock but who knows. It's quite possible there is some MIM in the CZ but they seem fond of machining things. CZ rifle and Rem 11-87 both fine. I think it's safe to say the Weatherby Mk V and Browning Mod 85 don't have MIM in either of them.

No broken parts in any of my guns actually (knock on wood). At least none that weren't the result of a "field upgrade" or "Oops! Damn".

 

[scrappydoo]

The only part I've had break on any of my 1911's thus far has been an MIM ejector.

 

[larry starling]

I had a thumb safety brake on a Springfield I use to own at just over a 1000 Rd's. Replaced part and put several thousand more rounds with no issue's. Gun was sold along time ago and the gentleman I sold it to has had no further issues from it. I guess the mim v/s tool steel debate is alive and well. Thanks 1911tuner for the very informative post's.

 

[Old Fuff]

When a gun part is designed to be made using MIM technology the designer usually takes into consideration the strengths and weaknesses of this manufacturing method and avoids the obvious weaknesses. Smith & Wesson and Taurus are both using MIM hammers and triggers, but these parts are not identical clones of the machined parts that were previously used.

The problem with MIM parts in the 1911 platform is that the parts in question are duplicates of those previously made from machined steel, and sometimes the configuration of the part does not ideally match the new technology used to make it. This in itself can be asking for trouble.

Then there is the matter of quality control. Most of the pistol makers that use MIM parts buy them from outside suppiers (Kimber is an exception I understand) and they are bought on the basis of lowest bid. Quality control - if there is any - is left up to the parts msanufacturer, not the gun maker who simply put the parts together. So it is possible that one batch of parts may be fine, where the next isn't.

So Tuner is right - how long a part holds up is a roll of the dice, which may be alright when the pistol is a big-boy's toy rather then a weapon. But all of my carry guns of the 1911 kind are pre-1965 manufacturer. Past experience tells me that infant mortality was never a meaningful issue with "real steel" parts, and over the long term the only breakage I've had is extractors, and that's very rare.

I would point out that we see all kinds of posts concerning problems with recent and current 1911 production from various makers, but none - or next to none - about those made before the 1970's or mid-1960's in particular.

 

[chieftain]

I would point out that we see all kinds of posts concerning problems with recent and current 1911 production from various makers, but none - or next to none - about those made before the 1970's or mid-1960's in particular.

No kidding. How many 1911 pistols do you think were made in the 60-70's as compared to today. Several orders of magnitude difference.

Secondly, it was COMMON in those days to take your NIB Colt and send it right to a Gunsmith, so it would work right the first time out. Steel parts and all. 1911's DID NOT HAVE A REPUTATION OF RELIABILITY, particularly out of the box.

That was the norm, not the exception

It was the reason I went to S&W revolvers and didn't start carrying my own personal CCW Jammatic weapons until the early 90's. Pistols were generally not reliable out of the box. I didn't trust the 1911 design again out of the box until 2004. I haven't been sorry or disappointed with either my Colts or Kimbers.

A lot of todays shooters just can't grasp that.

The singularly most common MIM failure I have witnessed, but not experienced, is the Springfield Ambi safeties breaking at various shooting matches. All the weapons were, from my questions new. So they were well within break in period.

With my Smiths, I just would polish everything up tweak a spring or two, and I would have an accurate, reliable weapon. Just wouldn't happen with a Colt 1911 Pistol.

Over all I think todays 1911 are much better made than the post war models. Prior to WWII, those pistols were stone reliable. But you were buying what by todays standards would be a full custom pistol.

With all this hogwash out, do I think tool steel parts are better than quality MIM parts? IF they are made properly. Maybe by a very small margin.

But not all tool steel parts are equal. But that is an argument for another pointless thread and poll.

Go figure

Fred

 

[Old Fuff]

Well lets see...

My reference to "pre 1970's and pre-1965 in particular" was intended to include all of the guns made by Colt and government contractors backwards to 1911, not just the half-decade between 1965 and 70, or between 1960 to 1970.

My personal experience with Colt's Government Model started during the later 1940's and has continued to date. They don't call me Old Fuff for nothing. Generally speakin the only buyers that sent off newly purchased Colt's (who were the only manufacturer of 1911 style pistols at the time) to gunsmiths were bullseye target shooters who usually wanted a full-house conversion. Field grade Colt's had an excellent and well deserved reputation for reliability, and would have been long gone decades ago if this wasn't the case. It is also safe to say that the military services would not have stuck with the pistol after World War One (or for that mater after World War Two) if individual 'smithing was necessary to make the gun run.

Up until the 1980's revolvers were the prefered handgun within law enforcement circles, most civilian users followed their judgment. If you have a preference for Smith & Wesson revolvers I won't dispute it. Otherwise I'd say (to stay on The High Road) that your experiences are completely the opposite from mine, and let those who are following this thread decide whatever they want.