Is It MIM or Forged?

[The Wizard]

Is there a way to tell if a part is Metal Injection Molded (MIM) or forged? I am talking in the context of walking through a gun show looking for parts. If I see a part I need/want is there a way of telling which it is?

 

[beekay]

It's not hard to tell, if you're used to seeing the two different parts.
It's more difficult to explain... Noticable differences in the surface texture and finish, along with the feel.
If you can find an older large frame with the target trigger and hammer and compare it to a new MIM piece, you'll see right away.
If someone at the gun show has an example of each that you can be shown, you'll see that the differences are obvious.

 

[aterry33]

MIM triggers are hollow on the back, forged are not.

 

[tomcatt51]

If you're looking at hammers and sears the MIM parts have nothing pinned. The forged parts have everything pinned.

 

[skeezix]

Triggers & Hammers

Here are a couple of annotated pictures of what to look for in MIM triggers and hammers.