How to recognize forged vs MIM triggers & hammer

Arthury · Aug 15, 2012

What criteria are you guys using to tell the difference between forged vs MIM triggers/hammers?
My understanding is that the forged ones are blackish and dirty looking while the MIM ones are bright and shiny.
And, this made sense since the MIM ones are poured (injected), like casting bullets, whilst the forged ones are machine-pressed and heat-treated.

E.g.
This is clearly a MIM trigger and hammer:
629-V Comp

... while this is forged:
Smith & Wesson Backpacker 44mag 2 1/2 $812.00 SHIPS FREE

The above is confirmed by S&W.

RobsTV · Aug 15, 2012

Good question.

Friend and I just bought a pair of used model 64-5's from SOSS.

Mine is older serial number before they switched to MIM.
My trigger and hammer are nice and clean looking.

His is later serial number, after switching to MIM.
His trigger and hammer are dark and dirty looking.

As to comparing to cast bullets, my air cooled are nice and shiny, but when they are heat treated they turn dark.

nipster · Aug 15, 2012

The forged and MIM hammers are virtually indistinguishable, except for the lack of case hardened "color", by the time they were making the transition to internal firing pin. The triggers apon closer inspection are very different looking. Look at the backside of the MIM trigger and it looks almost "hollow", whereas the forged part is solid. And the MIM part is not case hardened "colored".

Another thing, if the hammer has a firing pin on it, it's not MIM.

RobsTV · Aug 15, 2012

nipster said:
The forged and MIM hammers are virtually indistinguishable, except for the lack of case hardened "color", by the time they were making the transition to internal firing pin. The triggers apon closer inspection are very different looking. Look at the backside of the MIM trigger and it looks almost "hollow", whereas the forged part is solid. And the MIM part is not case hardened "colored".

Another thing, if the hammer has a spur on it, it's not MIM.

Thanks.
Confirmed the above on my older serial 64-5 with clean parts (nothing dark or dirty looking).
Spur on hammer and solid trigger backside.

Compared to S&W 500, which has a hollow backside of trigger.
But the MIM hammer does have a spur.

Rickkster · Aug 15, 2012

We had a sewer line disaster in the basement, so plumbers are here jack hammering etc, and I can't get down to my safe to grab a couple of my revolvers to take pictures. So here is a link to the very good FAQ, where there are some pictures of hammers and triggers and information on MIM. Maybe this will help.

Cheers,

Rick

http://smith-wessonforum.com/s-w-revolvers-1980-present/185299-500-magnum-nuts-faqs.html

Arthury · Aug 15, 2012

RobsTV said:
[...]
Friend and I just bought a pair of used model 64-5's from SOSS.

Mine is older serial number before they switched to MIM.
[...]

Are there any official paper work or confirmation from Springfield, MA that says that your model is pre-MIM and, likewise, your friend's is post-MIM?
May be it was the other way around?

RobsTV · Aug 15, 2012

Arthury said:
Are there any official paper work or confirmation from Springfield, MA that says that your model is pre-MIM and, likewise, your friend's is post-MIM?
May be it was the other way around?

The clean version I have is square butt with large cylinder release thumbpiece and serial number BPA7xxx. Thinking around 1994.

The friends shiny 64-5, except dark and dirty looking hammer and trigger, is round butt with narrow cylinder thumbpiece and serial CBY0xxx. Thinking around 1997.

I am sorry I forget who to give credit for this image, but thanks again. Also shown is the older version 64-5 with solid trigger.

Dpris · Aug 15, 2012

MIM triggers will have the hollowed-out area at the rear.
MIM hammers will have NO HAMMER-MOUNTED FIRING PIN. Spurs have nothing to do with it.

Simple as that, very obvious & easy to see & tell.
Denis

RobsTV · Aug 15, 2012

Dpris said:
MIM triggers will have the hollowed-out area at the rear.
MIM hammers will have NO HAMMER-MOUNTED FIRING PIN. Spurs have nothing to do with it.

Simple as that, very obvious & easy to see & tell.
Denis

Thanks.
Seeing as both my 64-5 and friends 64-5 have hammer mounted firing pin, I guess his version only had the trigger as MIM, which goes along with the posted image.

So then the darker color or dirty looking hammer/trigger compared to the rest of a spotless SS gun have nothing to do with MIM or not? Friends hammer/trigger condition looks exactly like the link Arthury's first post from Bud's.

M3Stuart · Aug 15, 2012

Dpris said:
MIM triggers will have the hollowed-out area at the rear.
MIM hammers will have NO HAMMER-MOUNTED FIRING PIN. Spurs have nothing to do with it.

Simple as that, very obvious & easy to see & tell.
Denis

+1

My 64-5 has a s/n that dates between the two mentioned above I think. It has a MIM trigger and a forged hammer (with the hammer mounted firing pin).

Robinett_11B · Aug 15, 2012

Arthury said:
What criteria are you guys using to tell the difference between forged vs MIM triggers/hammers?
My understanding is that the forged ones are blackish and dirty looking while the MIM ones are bright and shiny.
And, this made sense since the MIM ones are poured (injected), like casting bullets, whilst the forged ones are machine-pressed and heat-treated.

E.g.
This is clearly a MIM trigger and hammer:
629-V Comp

... while this is forged:
Smith & Wesson Backpacker 44mag 2 1/2 $812.00 SHIPS FREE

The above is confirmed by S&W.

"Clean" and "dirty" looking have absolutely nothing to do with it. As said above, an MIM trigger will be hollow and an MIM hammer will NOT have a firing pin attached. They made forged triggers in both case hardened and flash chromed finishes...which would yield "dirty" and "clean" looking parts respectively.

I'm about 90% sure the gun you linked to in the bottom photo is MIM.

Just because someone at S&W told you something, doesn't always mean it should be taken as 100% accurate.

ETA: The firing pin/no firing pin method is not always a sure way to tell if a gun has a forged hammer or not, as rimfire guns came with both case hardened and flash chromed hammers, but no firing pins.

Arthury · Aug 15, 2012

Robinett_11B said:
[...]
Just because someone at S&W told you something, doesn't always mean it should be taken as 100% accurate.
[...]

And, that's why I am asking you guys for more insights.
Thanks for the contribution.

Robinett_11B said:
[...]
They made forged triggers in both case hardened and flash chromed finishes...which would yield "dirty" and "clean" looking parts respectively.
[...]

Is this also true for MIM parts about case hardening and flash chrome?

Robinett_11B · Aug 15, 2012

Arthury said:
Is this also true for MIM parts about case hardening and flash chrome?

I'm fairly certain I've seen the telltale hollowed out triggers with the chromed finish, and I've seen hammers in person and in photos that looked much like case hardened steel, but were hollowed out MIM pieces. So, it'd appear so.

The material and finish used to make the hammers/triggers can usually be figured out by just looking at a couple detailed photos. With the 629 you posted a link to, I think it could be forged, as S&W was known to still use forged piece in their PC guns...but it could also just be made to appear that way.

FWIW, forged parts and MIM parts are known to work equally well.

Dpris · Aug 15, 2012

As said above, finish has nothing to do with it.
I should have mentioned the rimfires, but assumed this thread context was about centerfires.

The PC was still using forged hammers/triggers well beyond the regular production switch to MIMs.
Don'[t know if they still are.

Would not surprise me at all to see a gun with mixed parts.

S&W has never made a MIM hammer with a hammer nose firing pin, so if you see no pin, it's MIM.
MIM triggers will have the hollow, it's a re-inforcing feature for the material's design in that part.

As far as the "dirty" part goes, pre-MIMs had a particular case-hardened appearance that's not exactly duplicated in the MIMs (aside from the flash-chromed versions).
I consider the original older case hardened parts to be clean in form and not "muddy" in coloration, unlike the MIMs which I would define as "dirty-looking".
Denis

nipster · Aug 15, 2012

RobsTV said:
Compared to S&W 500, which has a hollow backside of trigger.
But the MIM hammer does have a spur.

I was aware that any MIM hammers had the firing pin on them. S&W did for a while make some revolvers that had the MIM trigger and forged hammer, maybe this is one of them.

s&wchad · Aug 15, 2012

Arthury said:
What criteria are you guys using to tell the difference between forged vs MIM triggers/hammers?
My understanding is that the forged ones are blackish and dirty looking while the MIM ones are bright and shiny.

You can't tell that way. Stainless revolvers had flash chromed triggers and hammers for a good part of pre-MIM production. As stated, the back of MIM triggers are hollowed out. With the exception of rimfire revolvers, the 547's and Performance Center revolvers, the change to MIM hammers coincided with the change to the frame mounted firing pin.

MIM hammers can be identified by what I believe are ejector pin marks on the sides. J frame hammers are easier to distinguish than the other frame sizes because they look completely different.
MIM trigger (note the ejector pin mark on the side):

J frame MIM hammer:

J frame forged hammers:

Performance Center guns had forged triggers and hammers long after the change to the frame mounted firing pin. I've heard that the PC recently (within the last few years) switched to MIM triggers and hammers, but I haven't seen a PC gun with them yet.

This link shows excellent photos of MIM and forged hammers.
http://smith-wessonforum.com/s-w-re...-if-innards-interchangable.html#post135785252

Dpris · Aug 15, 2012

Regardless of where the parts came from, regular production lines or PC, it does remain just that easy.

LOOK at the part.
If no firing pin, it's MIM (aside from rimfires). If hollowed out, it's MIM.

MIM is MIM & forged is forged, no matter where the gun came from.
Denis

Dpris · Aug 15, 2012

A correction.
After a PM from Chad, I checked my PC N-Frame from about 7 years ago.
It has a forged hammer & trigger, with a solid trigger, but it also has no hammer-mounted firing pin.

In the past I've discussed the forged parts issue with the PC, and I was told they were running off older production forged parts stockpiled exclusively for the Performance Center.
It's been a while since I've done anything with that gun & I thought it had the older hammer-mounted firing pin.

To update my statement I'll leave it at ANY trigger from any S&W factory source (aside from rimfires) that has the hollowed back is MIM.
On any NON-PC gun, if there's no firing pin on the hammer it's a MIM part.
On CURRENT PC guns, I don't know which they're using.

Otherwise, another way to determine if the HAMMER is MIM is to look for a faint line running down the center of the rear of the hammer body below the spur left by the molding process. There'll also be a raised round "sprue" on the right side of the hammer up near the top.

My apologies for any confusion.
Denis

scooter123 · Aug 15, 2012

I have a 625JM that was test fired August 10, 2011, so it's pretty safe to say it's just a touch more than one year old today. That revolver was delivered with a Forged Flash Chromed Serrated trigger and a Flash Chromed MIM Hammer. I also have a 2008 production model 620 that has smooth Flash Chromed MIM hammer and trigger. Point being that the MIM parts can be either Blued or Flash Chromed.

The ONLY way of being sure of whether a hammer is Forged or MIM is by removing the sideplate and looking at the part. As for the triggers, that hollow back is a dead giveaway for a MIM trigger.

Personally, I don't care one bit whether a part is Forged or MIM. Both processes as done by S&W have proven to yield parts with equal durability and one positive for the MIM parts is they usually don't require any "fitting". That 625 JM that featured a Forged trigger and Flash Chromed MIM hammer now features a 0.400 inch smooth MIM trigger in Blue and a matching MIM hammer in blue. Fact is I hate serrated triggers and replaced that Forged monstrosity with something that won't leave me bleeding.

Dpris · Aug 15, 2012

Adding to the list, if it DOES have a firing pin on the hammer, it's not MIM, as Nipster said .

Denis

How to recognize forged vs MIM triggers & hammer

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