Problem with Apex DCAEK sear spring on M&P - help

[Trekbike]

Okay I bought a Apex Tactical hard sear for my M&P when they first came out several years ago. I finally got around to ordering the remaining parts to bring it up to the DCAEK kit. I went to install the new sear plunger spring and it aint gonna work. It's a tad too small on the ID. (The spring kit comes with two springs and I did chose the right one for my gun. The other one is way larger.) The sear plunger won't seat on the Apex spring like the factory spring. When I install the Apex spring the sear only moves a small amount . Not even enough to enage the little arm inside the chamber area you flip down to field strip. What is happening is the spring is getting compressed too much and bottoming out because the spring ID is too small to go up to the correct shoulder on the sear plunger. See pictures below.

Has anyone else had this problem? I'll contact Apex on Monday but just looking for some feedback since I know a bunch of you guys have the DCAEK kit.

Also, I'm having a heck of a time trying to drift the rear sight off to do the USB. Yes, I did back out the set screw. It has only moved a sight amount and I'm banging it pretty hard with my punch. Any tips would be appreciated.

Apex spring on the left - factory M&P spring on the right

Factory M&P spring goes over the upper shoulder on the sear plunger.

Apex spring won't go over the upper shoulder.

Edited February 26, 2012 by Trekbike

[MarkInNashville]

All I can tell you is that I have 2 M&Ps (9 and 45). I had a gunsmith friend use his site pusher for the rear site(s). He ended up using a punch and really had to work hard to get them out. He did say that the XD is worse! lol I do know that it has to come off on the same side as where the ejection port is on.

[mikegideon]

I had to put my slide in a vise and use quite a bit of force with a punch. It wasn't an easy process..

[Trekbike]

Just wanted to update everyone on status. I've copied sections of my email to Apex, a follow up, and their response.

Email to Apex

....Several years ago when you guys first came out with the hard sear I put one in my M&P. Last week I went head and ordered the remaining parts to bring it to the same level as the DCAEK kit. I went to install the parts this weekend and had some trouble with the sear plunger spring. Mine is an older M&P with the smaller of the two springs. The Apex spring is a tad too small on the ID. The sear plunger won't seat on the Apex spring like the factory spring. When I install the Apex spring the sear only moves a small amount . Not even enough to enage the little wire arm inside the chamber area you flip down to field strip. What is happening is the spring is getting compressed too much and bottoming out because the spring ID is too small to go up to the correct shoulder on the sear plunger. I've attached pictures so you can see the issue.

> Have you had this issue before? I'm assuming I've received a fault spring but please comment. I currently have my gun still torn apart since I don't want to keep driving out the roll pin in the plastic frame and get it to the point it won't hold.

> Can you guys send a replacement spring overnight so I can get my carry gun back into service?

Email to Apex

Hello XXXX,

> I understand you were out yesterday. I ended up calling and talking to (XXXX at Apex). He explained that my problem described below was normal with the older type sears. He explained how to force the sear plunger down into the spring and I did this last night. I am disappointed that those instructions weren't noted in writing or was a part of the youtube video. XXXX also explained that you guys recommend changing out the sear housing to the newer large style sear plunger. What is the issue with keeping the smaller sear plunger? As far as I know there hasn't been a recall from S&W.

Email from Apex

Good afternoon XXXXX,

I can't say why the factory didn't do a recall on the guns with the smaller Sear Plungers and springs, but there are a lot of speculations out there that would certainly fit the bill. Aside from their reasoning, the factory has gone to the larger sear plunger and spring and it's now standard on all guns no matter what.

The mass of the smaller sear plunger and spring when compared to the Sear is incredibly tiny, which means that under recoil, the pressure wave that flows through the gun robs the sear spring of it's power momentarily right as the striker is coming forward and the trigger bar is resetting, causing the sear to fail to catch the striker. It's been discovered by he factory that this does not occur with the larger sear plungers because the mass of the sear and spring is much greater, along the lines of 4x the mass of the original.

We're working on new install videos for our existing product lines so we will make sure to mention that in the videos too.

I guess I'm going to look into a replacement sear housing that has the larger plunger.

Regarding the rear sight, I did get it off after getting a little more physical. Everything is back together and ready to go but I haven't shot it yet.

Edited March 5, 2012 by Trekbike

[mikegideon]

Good info to know. It's pretty scary how hard you have to smack that rear sight to make it move. I got mine off without scratching it, but it was a challenge.

[Chucktshoes]

I had the exact opposite problem with my rear sight. When I loosened the set screw, the rear sight slid off with finger pressure. After it shook loose on the next range trip, used blue loctite, when that didn't work I went ahead and installed night sights, used red loctite on the set screw and around the rear sight as it was still loose in the rear channel.

[Trekbike]

I had the exact opposite problem with my rear sight. When I loosened the set screw, the rear sight slid off with finger pressure.

Are you the original owner? If not, I'm guessing the previous owner had it off at some point. If you are, that is odd. As Mikegideon said, it's scary how hard I had to hit mine.

[Trekbike]

Odd. Just got another email from Apex now stating they sent me the wrong spring and will send me another. They do still recommend upgrading to the new style sear housing.

[Chucktshoes]

Yep, bought it new. Apparently the guy milling the sight channel was hungover the day mine came off the line.

[mikegideon]

i think S&W may have changed a spec in their later pistols. It was WAY too tight on the older ones.

[JPR1959]

One thing that might help getting off your old sights, would be to put your slide in the freezer overnight. Some people claim it helps, but I've never tried it. Of course, I have Xds, so I'll gladly have someone else get frustrated over changing my sights. Installing a trigger kit on XDs is really simple though.

[mikegideon]

I tried the freezer thing first. It took a padded bench vise, a brass punch, and some serious blows with a hammer.

[MarkInNashville]

I have 2 seperate M&Ps. The .45 is very new (I was the second owner but it was test fired 4 months before I took possition) while the 9mm was about 5 years old. Both took a LOT of force to knock the sights loose (I think the older 9mm had Brandon cussing LOL).