Shield APEX aluminum trigger and AEK: now getting failure to reset

[1KPerDay]

out of 6 mags 2 failures to reset. First round in the mag and 6th round in the mag. Can't use it for carry gun obviously. Do I have to adjust the "candy cane"? Apex videos for sheild didn't mention this and I was hoping to not have to mess with it.

Also I suddenly can't hit anything with this pistol, even from like 10 yards. I feel like I'm shooting blanks. Surely just unfamiliarity with the trigger but I fancy myself a pretty good pistol shot with multiple platforms and I was holding dead center, getting a good press/break, and missing the TORSO. LOLOL

I literally was yelling "WHAT?>!?" in the range. Weird.

OEM trigger was 8 and a quarter pounds with a jerky, stiff break that I couldn't shoot very well (but shoot poorly now). New trigger is smoother I guess, and is a 7 pound trigger, but isn't a night-and-day difference like the aluminum+FSS kit I put in my M&P CORE. I guess it spoiled me.

 

[Holmes375]

Sounds like you will need to address the trigger bar loop. I do on most of my installs simply to maximize trigger performance. Its not that hard to do, just go easy and use the gauges.

If you want a lighter break use the original factory trigger return spring instead of the Apex kit spring which is heavier.

 

[4v50 Gary]

Your firearm is useless right now. Install the original part if you want to work. Afterrmarket products are designed to do one thing: make the manufacturer money. Sometimes they work, sometimes they work only after they're worked on. Sometimes they're pure junk.

 

[1KPerDay]

Sounds like you will need to address the trigger bar loop. I do on most of my installs simply to maximize trigger performance. Its not that hard to do, just go easy and use the gauges.

If you want a lighter break use the original factory trigger return spring instead of the Apex kit spring which is heavier.

What gauges. And why would they make the return spring heavier than OEM?

 

[Holmes375]

The feeler gauges let you read the loop gap as you're opening/closing it a very small amount. Hard to "feel" by hand if you actually changed it when making the adjustment.

The Duty/Carry kit has a heavier return spring as the Apex sear reduces the trigger pull below what many are comfortable with. The heavier spring is intended to maintain a common carry pull weight. If you started out with an 8.25# pull weight and are still sitting above 7 lbs with the new trigger and sear then something is not right.

The trigger loop is adjusted to minimize over travel to a few thousandths. The loop is a soft steel that is rather easily adjusted. Apex has a video on that specific topic.


I'd recommend calling the folks at Apex about your scenario. They are very friendly and service oriented. Something sounds off on your change over and they can probably get you sorted out without issue.

Both these Shields have triggers just under and just over 5#:

 

[1KPerDay]

7 lbs with the gauge in the middle of the trigger like the OEM trigger, not at the tip. Do yours have the OEM return spring or the Apex return spring? I installed the kit properly. I have feeler gauges just didn't know if there was a specific tool you were using.

 

[Holmes375]

I have the Apex trigger spring in the 9mm, the factory spring combined with the Apex sear was too light for my taste. The 45 Shield has only the flat face trigger in it - factory sear, striker block and trigger return spring.

The Shield 45s seem to have a nicer trigger out of the box than the 9mm versions. More consistent, a little lighter and less gritty. The striker block channels are machined much nicer in the 45s, as well. That channel is the source of much of the trigger grittiness out there in M&P land.

 

[1KPerDay]

I've been googling lots of failure to reset and occasionally dead trigger issues with Apex and M&P pistols. Mostly with the old 1/16" sear spring but some more recently. Are any shields subject to sear flutter? Apex video on candycane adjustment mentions that you must have appropriate amount of overtravel; do you remove material from the rear of the trigger channel to increase overtravel? Can't find any video or other info on that. Apex hasn't gotten back to me on this.


Also some report they have had to CLOSE the gap of the candycane to fix their issues. That makes no sense to me; why would that solve anything?

 

[1KPerDay]

Added .005 to the candycane and filed the molding flash off the back of the trigger opening. Reinstalled OEM trigger return spring. Feels much better and no failures to reset so far in about 8 mags.

 

[Holmes375]

Over travel is a increased or decreased by adjusting the trigger bar loop. Opening the gap increases over travel, closing the gap decreases it.

Apex kits work only with the later sear block housings designed with the 1/8" sear spring and plunger. I believe this change occurred in 2011 or 2012. The Apex sear spring is also slightly stronger than the OEM. Use of the OEM sear spring combined with the Apex sear will result in sear flutter. The two springs are difficult to visually discern from one another. Yes, I speak from experience

Frame variation in the M&P pistols can indeed cause some trouble with the flat face trigger - or any aftermarket trigger. The trigger safety blade is designed to catch the frame thus preventing trigger actuation when not being intentionally pulled. Of the 33 Apex installs I've done I've had 2 guns (both were Shields) where I had to remove a few thousandths off the replacement trigger safety blade as the triggers were hanging up on the frame when the finger was placed high on the trigger face. I'm guessing the flashing you removed may have been causing a similar situation.

Sounds like you got your trigger bar loop adjusted nicely and you should be good to go. The variation in the pistols - and shooters - will really determine which trigger return spring one will end up using to achieve a nice pull weight for carry. Glad to hear yours is now closer to what you were hoping for. Good job of it!