It's a small part but important.  I had my firing pin retaining plate crack in two the other day on a kimber classic custom.  It cracked just above the firing pin hole.  I'm not bashing Kimber or anything but wanted to give a heads up.  I never thought MIM was that bad but am starting to think about replacing a few key parts after this.

The gun has about 3,500 rounds through it.

 

Did you notice after you were done shooting or did it stop you while you were shooting?

Quoted: Did you notice after you were done shooting or did it stop you while you were shooting?

I noticed it when I was taking it a part for cleaning.  It was probably cracked while I was shooting and stayed together.  It broke directly above the firing pin hole.  It's a cheap part to replace but a real P.I.T.A. if it breaks at the wrong time.  This is the first part failure I've had with any 1911.

Pictures

After reading these stories I have started to replace every part on my Kimber.

Kimber did (IMHO) a fantastic job on the frame , slide , barrel and fitting them together.

Everything else is being replaced with Wilson Bulletproof or Wilson std parts. Those that I can do myself (Slidestop, Extractor (tensioned, not shaped) Firing pin plate, mainspring housing, firing pin) are first to go.

When the gun gets sent in to a real smith for trigger job , etc... everything else gets pulled and replaced with barstock parts.

It's a shame they put MIM in these pistols, really nicely built pistols, except those MIM parts.

The MIM may never break, but then again, for 250 in parts, you never have to wonder.

Quoted: Pictures

If I send them to you, can you post them?

Actually I've had the non-MIM ones break too.  the Yost-Bonitz guy told me they all break, eventually.  
I don't buy MIM though.  

I did as our esteemed Moderator suggested and replaced the slide stop, firing pin stop and extractor with Ed Brown bulletproof parts on my Warrior.  Good call SGB!

Quoted: I noticed it when I was taking it a part for cleaning.  It was probably cracked while I was shooting and stayed together.

This is exactly why I always clean my CCW 1911 after shooting it.

I've had the firing pin stop break on a Browning HP-35 from the FN plant in Belgium.  It's a part that wears.

Yours died a little early, though, I'd think.  

Quoted: Actually I've had the non-MIM ones break too.  the Yost-Bonitz guy told me they all break, eventually.   I don't buy MIM though.

I've never had one break before and I have several 1911s with round counts well over 10K. I've never seen a GI one break either.

I have seen several MIM ones that cracked tho. The hammer strike on  such a part has to be pretty hard on it, and I can see where a internal flaw could cause it to crack.