Sprinfield 1911 45ACP Range Officer and MIM (?) parts

Did the Springfield RO use MIM parts?  I think I have the term correct. They were/are parts made of "powdered metal" which is/was "compressed and formed".

Yes, the factory parts are MIM. It is a common practice to replace the RO internals with quality parts machined from bar stock, such as C&S, EGW, etc.

Yes. All lower end off the shelf 1911's have MIM, metal injected molding, parts.

Bill

As others have mentioned yes. They can be serviceable is some cases for quite some time. The firing pin stop on one of mine had 6k worth of live ammo and probably 2x that in dryfire with the stock mainspring before it failed.

I'm definitely not a pistolsmith so I'll defer to any of our distinguished smiths that hang out here.  However, I wonder if the MIM parts of today might be good enough.  They surely have to be better than in earlier years with advances in manufacturing.  Quailty of MIM parts probably depends more on who produced them.
Phil

i had a job to machine a 20 shafts that had 8mm X 1.25mm tapped hole 20mm deep is 304SS on the ends
 I know that the tapped hole was a problem I talked to MSC and a Guhring spiral point bottoming tap made from powdered metal was recommended. Wasn't cheap quite a bit more than HSS tap! I got it and used it in torque limiting tapping head. Tap did all 40 holes without a problem. Shafts were ordered again and the same tap did another 40 holes. I've also used it to do a few other tapped holes in SS. Simply put I was surprised that the tap worked better than HSS

Just a quick comment on powdered metal as used in MIM parts vs. that used in tool steel, e.g. the taps that Froneck referenced above.

The goal in MIM is to mass produce dimensionally finished, or nearly finished, components with complex geometry using the injection molding process.  This reduces or possibly eliminates costly machining operations.  The metal powder is combined with a binder to facilitate the injection process.  The binder is removed in a subsequent operation.  The steel is low alloy but certainly can be good quality.

The goal with powdered metal tool steel is to achieve a tighter and more uniform grain structure that will produce a better steel than the typical cast ingot/rolling process.  It is a process that bonds very small particles (powder) under extremely high pressure and yields bars which are then machined for the desired purpose.  These are high alloy (high dollar) steels typically used to create mold tools, cutting tools, tool & die components, etc.

Yes they are high dollar, tap cost 4X the price of a general purpose HSS tap. Worked great too! My point was that powered metal frames can be better than those made from alloy steel. That is if they want quality powered metal and process used in their frame. So a powdered metal frame could be better than alloy steel frame but may not be.
 Over the years I have machined items like sprockets and gears that when used lasted longer than previous one made from steel. Usually they don't produce chips, kinda like machining cast iron.
 I don't know what Springfield is using, only time will tell how well the parts preform.

MIM Parts. The hammer and sear will hold a trigger job for a while. But the gun will definitely double if you do a trigger job after about 3000 rounds. I had a stock RO and TRP and in both cases the factory parts did not last too long.

I've been fooling around with a SA Prodigy I bought last April. Replaced firing pin and its return spring with normal spring and EGW steel pin. EGW slide stop made a good lock up better. 
Kept the MIM hammer, sear and disconnect, used True Radius jig to fit sear and shortened the hammer hooks to .020 and squared up, turned out pretty good.
About 2200 rounds later the MIM sear tip started to get buggered up. I had a new EGW sear on hand so fitted it up with the MIM hammer. The hammer hooks looked great still.
Ran a hundred rds since, so far its great. Gonna test some GINEX primers tomorrow so it will see a few hundred rounds along with a S&W M&P core.
I have a SA RO with fitted OEM MIM sear and hammer thats still great after at least 3500 rds. I guess its hit and miss on MIM longevity after having been fitted.