MIM parts? How to recognize?

[chevypilot]

Ok, I'm new enough to not know how to recognize a MIM part. Is both the hammer and trigger on this 686-5 MIM?

 

[chevypilot]

Ok, I'm new enough to not know how to recognize a MIM part. Is both the hammer and trigger on this 686-5 MIM?

 

[CMcDermott]

From the mottled grey "case-coloring" I would say yes, they are MIM parts. The trigger is easy to confirm, does it have a deep groove on it's back side? If yes, then it's a MIM, if it's solid then it's forged. The hammer is harder to tell, but you can usually make out what look like casting lines and sprue marks on them which are from the MIM process; which starts out with a mold that is filled with a mixture of powdered metal and various binders and fluxes. MIM stands for Metal Injection Molding. And the final parts are case-hardened, but don't get the pretty swirling colors of the forged parts, just the non-pretty dark gray mottling that appears in your photo.

 

[chevypilot]

Thanks, and yes to the trigger question. I was 99% sure as I have others with forged parts that just look beautiful. I'm going to send this one back and ask S&W to replace with forged while doing an action job and maybe some engraving

 

[dsf]

I may be wrong, but aren't all hammers used on Smith centerfire handguns with a frame mounted firing pin MIM?

 

[pinkymingeo]

Forged parts are not functionally superior and are, in fact, often inferior. MIM parts tend to fit together much better than forged and provide extremely smooth actions. Manufacturing processes have advanced a little since Truman was president, though a lot of S&W revolver fans seem to believe time stood still right about then, and that any newer developments must be bad, if not sacrilegious. Go to the handloading section and you'll find guys seriously discussing the merits of reloading manuals so old that half the powders in the data aren't even manufactured anymore, while seriously examining how to duplicate loads from 60-70 years ago. Oh, well. I guess 70-80 years from now guys on this forum, or it's equivalent, will be talking about the good old days of MIM.

 

[Hoplophile]

Or the good old days when citizens were allowed to own guns. :-(



As for the older loading manuals, several of the "recommended" loads back then exceed the maximum loads of today's manuals. Lawyers, don'tcha know.



Like the stupid scribe markings on some guns, "Before using gun, read instruction manual available free from..."

 

[s&wchad]

Originally posted by sailing1801:
I may be wrong, but aren't all hammers used on Smith centerfire handguns with a frame mounted firing pin MIM?

That’s correct for regular production, but the Performance Center still doesn't use MIM triggers and hammers and they brag about it.
http://www.smith-wesson.com/webapp/wcs/stores/servlet/P...rn=15714&isFirearm=Y

Non-PC guns with the frame mounted firing pin (except older .22's) have MIM hammers. MIM triggers are hollowed out on the back and easy to spot. I believe some guns had MIM triggers before the MIM hammers were introduced. MIM works fine, but the old color case hardening was a lot prettier.

MIM (notice the back of the trigger)

Old style case color hardened (Mmmmmmmm!)

Sometimes it's OK to be superficial!

 

[bountyhunter]

Originally posted by chevypilot:
Ok, I'm new enough to not know how to recognize a MIM part. Is both the hammer and trigger on this 686-5 MIM?

Trigger for sure,hammer looks like it. You can see the holes on the side which are the fill places in the mold.