And what parts?

On my guns I've had two safety failures, both at the joint.  On guns that I've worked on, I've seen failures of safeties (same as above, as well as lever breaking off), slide stops, firing pin stops, and a couple hammers.  I was talking to the head armorer of Maricopa County Sheriff's Office yesterday, and he has seen a few safeties with sheared off internal studs on duty weapons  Quite a few deputies, himself included, carry Kimbers, but they have seen very few MIM failures.

I'm sure others will chime in, but I've seen people post with much more disturbing MIM failures, such as barrel bushings and mainspring housings.  I say these are more disturbing simply because you would not expect these things to break, and I've never seen a non collet bushing break.

Breaks on mainspring housings?  Really?  That would surprise me.  How would it break anyway?  It's not slamming into anything....

Let me see if I can dig up a pic of an MSH breakage.  I can't remeber if I saw it here or on a 1911 forum.  Bushings are low stress, as are mag releases, and I've seen pics of both here.  Personally, I don't really worry about that stuff, though I have been known to completely de-MIM Kimbers.  I usually just replace the hammer and sear (more for a better trigger job than anything else), as well as the slide stop.  The rest doesn't worry me at all.

I've seen two ambi thumb safeties break on the same eclipse and I've seen the plunger tube fall off during a range session on a compact their custom shop had just "tuned". That's three failures in about a one year time span.

Yeah, the plunger tube came off on mine too.  Only 600 rounds.  I had it re-staked by a local smith.  I've got a bunch of parts coming in from Brownells to replace the MIM parts, but I was starting to feel like I was just being paranoid.  Maybe not.

Not sure if it has anything to do with MIM, or just my shit luck. I was shooting my Warrior yesterday and at exactly round 1537 I noticed my front sight looked strange. Finished my last three rounds at 25 yards and noticed that the end of the front sight that housed the tritium insert was gone. I first thought the insert fell out but the end of the sight actually broke. Bizarre.

The only failure I have seen is a barrel bushing that shattered sending the recoil spring down range. This was on a gun that probably hadn't seen a new recoil spring since it left the factory and had several thousand rounds through it.

Quoted: The only failure I have seen is a barrel bushing that shattered sending the recoil spring down range. This was on a gun that probably hadn't seen a new recoil spring since it left the factory and had several thousand rounds through it.

I wonder if a major source of problems for MIM is people not changing out springs and doing routine maintenance like they should?  I replace my recoil and firing pin spring every 1000 rounds on my M1911s.  Certainly a weak spring would cause increased battering.  Not that it's an excuse for those kind of parts to break (they shouldn't anyway)....

It is hard to say what the cause was. It could have been neglect but this was a pretty spectacular break. The bushing literally shattered. I see tons of under-sprung guns at teh range every time I am there but I have never seen a failure like this.

We reinstalled the same spring with a new bushing (provided free of charge by Kimber) and ran a magazine. Ejection was consistent but a bit vigorous. Brass was in a nice pile about 17-18 feet back from the shooter, so obviously the spring was past it's prime.