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  #1  
Old 12-10-2024, 01:20 PM
marvin02 marvin02 is offline
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M&P FPC information, complete disassembly & replace hammer spring M&P FPC information, complete disassembly & replace hammer spring M&P FPC information, complete disassembly & replace hammer spring M&P FPC information, complete disassembly & replace hammer spring M&P FPC information, complete disassembly & replace hammer spring  
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Default M&P FPC information, complete disassembly & replace hammer spring

The six bolts holding the receiver together are 4-40 by three-quarter inch, Button head. The nuts are nylok, nuts 4-40.


Here is a video:


That channel has a lot of info on the FPC.


If you are going to disassemble the receiver you want to have replacements bolts on hand. The tiny torx heads strip very easily.


Amazon links:









Smith & Wesson has revised the firing pin and spring:




I have an early model and have had zero issues but I guess some were having light strike issues.

Last edited by marvin02; 12-10-2024 at 01:26 PM.
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  #2  
Old 12-10-2024, 01:23 PM
marvin02 marvin02 is offline
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M&P FPC information, complete disassembly & replace hammer spring M&P FPC information, complete disassembly & replace hammer spring M&P FPC information, complete disassembly & replace hammer spring M&P FPC information, complete disassembly & replace hammer spring M&P FPC information, complete disassembly & replace hammer spring  
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Default Hammer Spring Replacement

One of the complaints I hear from people at steel matches who try my FPC is that the trigger is too heavy. Here is a series of videos showing how to lighten the trigger pull:








I have done this to my FPC. Here are my results:


Out of box - 5 lbs, 2 ounces

After 100 rounds - 4 lbs, 8 ounces

After 500 rounds - 4 lbs, 6 ounces

After 1,000 rounds - 4 lbs, 3.4 ounces

After reduced power hammer spring: 3 pounds 5 ounces


So on mine it reduced the pull by 1 pound. Changing the hammer spring didn't effect the reset. It did make it noticeably easier pull the bolt handle back when the hammer was uncocked.


Went to the range today and tested. No light strikes.


BLAZER 124 - 9 rounds ( all I had)

REM UMC 124 - 31 rounds

FIOCCHI 124 - 15 rounds

PPU 124 - 41 rounds

S&B 124 - 20 rounds


Doing a detailed take down on the FPC allowed me to deep clean it. Everything except the barrel went in my sonic cleaner.


Edit: Even if you don't want to change the hammer spring the videos above are a great look at the FPC internals.

Last edited by marvin02; 12-10-2024 at 01:27 PM.
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  #3  
Old 12-10-2024, 01:24 PM
marvin02 marvin02 is offline
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M&P FPC information, complete disassembly & replace hammer spring M&P FPC information, complete disassembly & replace hammer spring M&P FPC information, complete disassembly & replace hammer spring M&P FPC information, complete disassembly & replace hammer spring M&P FPC information, complete disassembly & replace hammer spring  
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M-Carbo now has flat triggers and a trigger spring kit for the FPC:


Smith and Wesson FPC Accessories - M*CARBO


No MCarbo install video though.

Edit: I am not affiliated with either of the YouTube channels linked above. I hope someone gets some useful info from this thread.

Last edited by marvin02; 12-10-2024 at 01:25 PM.
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Old 12-10-2024, 01:33 PM
marvin02 marvin02 is offline
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Field stripping the FPC:

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Old 12-10-2024, 01:35 PM
marvin02 marvin02 is offline
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Default FPC Bolt Disassembly

How to disassemble the bolt on the FPC:


If you have an early model your bolt may have roll pins (mine does). I have taken my bolt apart and the pins came out with no problem.
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Old 12-10-2024, 01:41 PM
marvin02 marvin02 is offline
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Here is another take on detailed disassembly:



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Old 12-10-2024, 07:48 PM
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Bear in mind that in a hammer fired blowback action, cocking force of the hammer helps resist the bolt opening.
By using a lower power hammer spring you are increasing bolt velocity. In engineering, everything is a trade off. To have more of something, you need to give up something else. Here they are trading a lighter trigger pull for some degree of increased recoil and increased wear. The FPC is pretty stout though so maybe it’s fine.
Just understand the trade offs and make an informed decision.
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Old 12-11-2024, 01:23 PM
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Another thing I just noticed. In the Four Peaks Tactical trigger job Part 3 video, at 6:20 he shows reassembly of the bolt catch plunger and spring into the feed ramp block, he installs those parts backwards. The closed end of the plunger should face rearwards to engage the bolt catch. He has the plunger facing forwards.
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Old 12-11-2024, 11:28 PM
marvin02 marvin02 is offline
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Quote:
Originally Posted by JRD View Post
Another thing I just noticed. In the Four Peaks Tactical trigger job Part 3 video, at 6:20 he shows reassembly of the bolt catch plunger and spring into the feed ramp block, he installs those parts backwards. The closed end of the plunger should face rearwards to engage the bolt catch. He has the plunger facing forwards.
So I've watched Part I and part III and he puts the spring in the same orientation that he took it out.

I've attached screen grabs from both parts. They show that the spring is toward the feed ramp. I know that mine is installed with the spring toward feed ramp.
Attached Images
File Type: jpg Trigger Part 1 10M30S.jpg (61.6 KB, 15 views)
File Type: jpg Trigger Part 3 6M19S.jpg (53.0 KB, 17 views)
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Old 12-11-2024, 11:58 PM
JRD JRD is online now
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The screen grabs demonstrate my point. The bare end of the spring should face the muzzle. The flat end of the plunger should face rearward to engage the bolt catch.
Regardless of how it was when he first takes the spring out, it was in there backwards.
Maybe it’s a great design and will still work with the plunger installed backwards…
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Old 12-12-2024, 12:18 AM
marvin02 marvin02 is offline
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Quote:
Originally Posted by JRD View Post
The screen grabs demonstrate my point. The bare end of the spring should face the muzzle. The flat end of the plunger should face rearward to engage the bolt catch.
Regardless of how it was when he first takes the spring out, it was in there backwards.
Maybe it’s a great design and will still work with the plunger installed backwards…
What's your source for this info? I would love an exploded view of the FPC or any other info you have.
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Old 12-12-2024, 02:40 PM
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S&W has not published an exploded view of the FPC so there are no pictures to share.
I've got some friends at the factory who are very familiar with the FPC and confirmed the design intent of the plunger for me.
I know it may sound sketchy that some guy on the internet says he knows someone who knows the answer... but I assure you I'm not inclined to spread any incorrect information on this forum.
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Old 12-12-2024, 03:51 PM
marvin02 marvin02 is offline
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Quote:
Originally Posted by JRD View Post
S&W has not published an exploded view of the FPC so there are no pictures to share.
I've got some friends at the factory who are very familiar with the FPC and confirmed the design intent of the plunger for me.
I know it may sound sketchy that some guy on the internet says he knows someone who knows the answer... but I assure you I'm not inclined to spread any incorrect information on this forum.
Thanks for the reply. I'm just trying to share what info I can find about the FPC and welcome pointers to any sources that have additional info.
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  #14  
Old 12-13-2024, 05:58 AM
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I like the idea of a flat-face trigger, but dang that's pricey!
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