Excess play in sear housing

[cbr6864]

Anyone have excess play in sear housing? Looking down if I grab the front I can lift the front up at least a 1/16" on my 40c but on my fullsize there is zero play. I sent my 40c in and S&W claimed to be within tolerance. Seems any movement of the sear would be bad considering the M&P striker is damn near fully cocked back.

 

[rsrocket1]

Yes, my sear housing block has play in my M&P 40 FS. The thing is, the block is locked in when the slide is in place so there is no problem. Does your housing block move back and forth or does it simply have a slight rotational play?

 

[cbr6864]

No my block on my 40c only moves up and down in the front part facing barrel. I see how movement would be limited to amount of play allowed when slide is on. I'm guessing its caused by slight variations in the production of the frame.

 

[OKFC05]

My best example of meaningless play in a gun was a Remington 11-87 shot gun I bought to shoot at the base skeet range when I was still on active duty. When the bolt was locked back, I could make it sound like castanets if I shook it gently just right, and I would mumble about hoping it wasn't going to fly apart when I shot it. Nobody crowded me when I was on station.

 

[ggibson511960]

Me Too!

I had the exact same problem on my 40c. Made a mess of the trigger pull. I solved it by pulling out the block and carefully cutting a few strips of air conditioning duct foil and pressing in place. Only takes a few thousandths to wedge the housing up a bit in the front. The pin holds it steady in the back. Solved the problem completely and greatly improved the trigger pull. The rocking sear block would cause a "step" in the force-distance curve of the trigger pull. Mine was so bad you could see the safety lever moving up and down. Foil shims were easy to fit. Shade tree gunsmithing, but they work.

 

[cbr6864]

@gibson thanks for advise I just might have to give it a try. The trigger between my compact and fullsize is completely different. I know it's the actual frame out of specs as before I took my buddies 40c sear housing and placed it in my gun and my sear housing in his gun. My gun still had play while his didn't.

 

[cbr6864]

Going out to any M&P experts my 40c sear has a dimple on the side and my 40 fullsize is stamped with an R. Both have H stamped trigger bars. Was there a recent change in the sear?

Wish I could get both my fullsize and compact triggers to feel the same. I'm going to try and get S&W to replace the frame. I just can't believe that they claim any amount of movement is within spec.

 

[Jdugan4859]

Seems any movement of the sear would be bad considering the M&P striker is damn near fully cocked back.

If you are worried about the sear tripping without pulling the trigger and having an accidental discharge, don't worry about that. The striker block would prevent the stricker from moving forward and hitting the primer, that's what the stricker block does. If the sear did trip, the worst that would happen is you would have a dead trigger if you needed to fire the weapon, and you would have to rack the slide.

 

[cbr6864]

If you are worried about the sear tripping without pulling the trigger and having an accidental discharge, don't worry about that. The striker block would prevent the stricker from moving forward and hitting the primer, that's what the stricker block does. If the sear did trip, the worst that would happen is you would have a dead trigger if you needed to fire the weapon, and you would have to rack the slide.

The thought of any failure on my carry gun is beyond disconcerting. I know the firing pin block should stop the gun from discharging but the gun shouldn't do this. I'm going to send it in again to S&W and demand they fix the issue this time.


Here is a vid showing the problem...in case your wondering that's my aquarium in the background noise.

http://youtu.be/4D0bCwVGN28

 

[ggibson511960]

No Worries re. Accidental Discharge.

The thought of any failure on my carry gun is beyond disconcerting. I know the firing pin block should stop the gun from discharging but the gun shouldn't do this. I'm going to send it in again to S&W and demand they fix the issue this time.


Here is a vid showing the problem...in case your wondering that's my aquarium in the background noise.

http://youtu.be/4D0bCwVGN28

If you look down into the frame while pulling the trigger, shown very well on your video, you will see that the wiggling sear block actually causes more sear engagement. The first 1/8 in. of trigger bar movement only serves to activate the striker block. The sear block stays put until the trigger bar starts pushing on the sear in the second 1/8 in. of travel. The angles are such that the sear and sear block tilt up (the source of all the trouble) and actually engage the striker sear deeper. The sear block is rotating about the rear roll pin that holds it in the frame. This is what causes the staging and bad trigger pull. There is no danger of an accidental discharge unless you just can't handle the gritty staging trigger pull. Punch out the roll pin, lift out the sear block, and glue in a shim. Less trouble than sending the whole rig back to S&W. Yours will be comparatively easy because you have no safety lever flopping around in the way. I would be willing to bet that S&W will not fix the problem as well as you can because of corporate paranoia. Maybe a fitter with a pile of sear blocks and frames to swap around with could find a pair that fit better, but the basic design flaw remains. The sear block is held in position by a roll pin at the back (good) and a close fit at the front (not go good, but fixable).

 

[cbr6864]

If the front of the sear block moves up that mean the rear is moving down which actually moves the sear away from the striker. I'm going to send it in again demanding they either fix the gun or change it out with one that functions properly. No matter what the design is you shouldn't have any additional movement in the sear other than the actual trigger pull. It is a huge design flaw with a single pin and removable sear block housing.

The trigger on my 40c feels like complete garbage when compared to my fullsize because the sear on my fullsize has a proper fit. Shims will not fix the issue has in order for the block to be level it must be all the way down in the front. If I shimmed the front up there would be excessive wear on the slide rails. Besides you shouldn't have to jam pieces of foil tape in a gun you just bought in order for it to function.

I sincerely hope they address the issue and fix it this time...if not this will be the last S&W product I ever buy.

 

[cbr6864]

Update I sent out an email after work and received a response within a few hours strange my two previous emails went with zero response. Might have had to do with my wording this time regarding possible negligent discharge due to the sear rocking in the frame resulting in injury or loss of life. I'm requesting S&W to certify the gun is 100% in proper working order and free of any defects.

Hopefully I get it returned in proper working order this time.



I think the problem is they don't take the time to fully read what customers submit or look at supplied videos. They simply fire a mag through the gun then state within factory specs.

 

[tonesurfer]

Had a similar problem (your's actually seems worse than mine) with the front locking block on my FS9. Sent in in, they sent it back - it's fine. Sent it back again telling them they were out of their minds, they sent it back again - it's fine.

S&W Customer Service, we sell more Glocks than Glock.

http://s893.photobucket.com/user/tonesurfer/library/MP%20Locking%20Block

 

[ggibson511960]

Levers & Pivoting

If the front of the sear block moves up that mean the rear is moving down which actually moves the sear away from the striker. I'm going to send it in again demanding they either fix the gun or change it out with one that functions properly. No matter what the design is you shouldn't have any additional movement in the sear other than the actual trigger pull. It is a huge design flaw with a single pin and removable sear block housing.

The trigger on my 40c feels like complete garbage when compared to my fullsize because the sear on my fullsize has a proper fit. Shims will not fix the issue has in order for the block to be level it must be all the way down in the front. If I shimmed the front up there would be excessive wear on the slide rails. Besides you shouldn't have to jam pieces of foil tape in a gun you just bought in order for it to function.

I sincerely hope they address the issue and fix it this time...if not this will be the last S&W product I ever buy.

Do what makes you feel comfortable. If you look closely at the geometry of the pinned sear block, the engagement plane of the sear and striker sear are about 5/32 in. (0.157 in.) ahead of the rear pin. The rear pin is pretty tight, requiring a lusty punch to drift from the frame. Thus the rear point of fixity is a rotating pinned connection. The ill fitted sear block and sear rotate clockwise around the pin (viewed from the left) and move the sear into deeper engagement. Mine would raise the slide ever so slightly. You could feel it more than see it as the trigger was pulled if you touched the top of the slide. I don't want to take mine apart to measure the thickness of my shim stack, but I would guess no more than 0.005 in. The frame rail is centered over the pin and would only rotate up a small fraction of 0.005 in. If you look closely, S&W tapers the frame rails ever so slightly in profile so they are more elliptical than rectangular, perhaps to make them easier to manufacture (MIM cast), or maybe to accommodate tolerance accumulation from sear blocks flopping around. The shim stack doesn't change the rear frame rail position after firing. It just holds it constant throughout the cycle. A loose sear block is going to rotate upward from trigger backlash anyway.

I agree that the trigger pull as manufactured is a mess, but it's safe. A little tuning has made a huge difference in mine, even without add on trigger parts.

 

[cbr6864]

Bottom line the gun should not do this there shouldn't be a huge variation between the same model. The apparently have an issue with their casting procedures I'm guessing some of the molds are out of spec. More to the point they should have fixed it the first time! The trigger on my 40c is complete garbage as you can feel the sear jump all over. As I said having to shim up the sear block in a brand new going with tape is insane. I think the entire reason is cost savings as they can produce a buch of sear blocks then dump them in whatever model and as long as the gun goes bang it's all good I guess.

Having a carry gun that by design is more or less a SA (no matter what S&W claims) with a sear block flopping around is a little scary. I know there is a firing pin block but you shouldn't have to rely on that. Even putting a thump safety on would do no good as all the M&P safety does is block trigger movement it has nothing to do with locking the sear.

 

[msr]

Any update from the two posters with loose sear housing blocks? What did Smith say?