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Discussion Starter · #1 ·
Good Morning,

I am trying to help a friend get his M&P 40 9mm squared away .First let me say that I am an experienced gunsmith but in no way an expert on this platform. My friend had an APEX trigger installed by a co-worker. After the install, the firearm appeared to function-check normally. The striker released when the trigger was pulled and the disconnector reset normally. When he took it to the range, it would not fire. The primers on several cartridges that he attempted to discharge showed very light strike marks. The striker block plunger works normally. I checked the striker protrusion with a firing pin protrusion gauge by depressing the plunger and pushing the striker fully forward. It measured .019". Is this a normal condition for this firearm? I completely disassembled it and the only thing I have found so far is that the trigger spring was installed upside down. I have Doug at APEX in the loop as well. Any help would be appreciated. Thanks!!

Semper Fidelis,

CA
 

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I had an issue on a 1.0 FS M&P 9MM. Well, two problems.

One sounds similar to yours. Small indent on the primer but not firing. Happened 3 or 4 times per magazine. Timing issue on mine. The striker block was not being moved completely up/out of the way by the arm on the trigger bar before the striker was released by the sear. The striker would hit the striker block as it went forward (sometimes) and that would slow the striker down enough to keep it from lighting off the primer.

I think there used to be a video on the Apex web site that explained how to fix that (what to adjust and check).
 

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Discussion Starter · #3 ·
I had an issue on a 1.0 FS M&P 9MM. Well, two problems.

One sounds similar to yours. Small indent on the primer but not firing. Happened 3 or 4 times per magazine. Timing issue on mine. The striker block was not being moved completely up/out of the way by the arm on the trigger bar before the striker was released by the sear. The striker would hit the striker block as it went forward (sometimes) and that would slow the striker down enough to keep it from lighting off the primer.

I think there used to be a video on the Apex web site that explained how to fix that (what to adjust and check).
That's what the Apex CS guy said as well. They are sending me an improved version of their striker block to install. I'll try that first. Thanks for the info!
 

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I had an issue on a 1.0 FS M&P 9MM. Well, two problems.

One sounds similar to yours. Small indent on the primer but not firing. Happened 3 or 4 times per magazine. Timing issue on mine. The striker block was not being moved completely up/out of the way by the arm on the trigger bar before the striker was released by the sear. The striker would hit the striker block as it went forward (sometimes) and that would slow the striker down enough to keep it from lighting off the primer.

I think there used to be a video on the Apex web site that explained how to fix that (what to adjust and check).
That’s definitely a timing issue; which I believe is what the OP is most likely dealing with. I’d contact Apex for their guidance. I’ve read that there’s a “loop” in the trigger bar that sometimes needs “adjusting” after some of their components are installed. I’ve never had that problem myself; but many others have…
 

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Discussion Starter · #5 ·
That’s definitely a timing issue; which I believe is what the OP is most likely dealing with. I’d contact Apex for their guidance. I’ve read that there’s a “loop” in the trigger bar that sometimes needs “adjusting” after some of their components are installed. I’ve never had that problem myself; but many others have…
That's the consensus at Apex as well. They are sending me an upgraded striker block. Their customer service is fantastic.
 

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You need to adjust the candy cane until you can shoot a cheap Bic pen(the kind with a removable cap) across the room. I know it sounds crazy but clear your pistol,and put the pen in barrel pointed slightly up so fireing pin will hit flat end of pen,it should launch impressively when you pull the trigger. I had the same issue and one call to Apex was all it took.Apex has a video on how to adjust the loop and check with feeler gauges. Excellent customer service!
 

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You need to adjust the candy cane until you can shoot a cheap Bic pen(the kind with a removable cap) across the room. I know it sounds crazy but clear your pistol,and put the pen in barrel pointed slightly up so fireing pin will hit flat end of pen,it should launch impressively when you pull the trigger. I had the same issue and one call to Apex was all it took.Apex has a video on how to adjust the loop and check with feeler gauges. Excellent customer service!
In prehistoric times, pencil's were used for that purpose; and it was called “the pencil test” to determine if the firing pin block was timed properly on Colt Series 80 1911s. 👍
 

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I did it back in the early 80's with a regular Colt 1911. Stuck that darn pencil in the ceiling above the Chief's desk. Had to get up on the desk to reach that pencil. I don't think he ever noticed the extra hole in that celotex ceiling. Only other guy that saw it was my partner and he didn't tell the Chief.
 

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I'm wondering if the striker spring is too weak for some reason.

Definitely not trying to be a know it all, but the striker block/trigger bar mechanism is super simple. Unless one or the other were severely out of spec, I don't see how that could be causing this.

(runs away with his head covered :) )
 
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