I have the M&P 9mm full size with the magazine safety. So I put 1000 rounds through it. 250 the 1st time, 300 the 2nd time, 200 the 3rd time, and 250 the 4th time shooting it, after every time I came back from the range I cleaned it. I never took the firing pin out to clean. Now after 1000 rounds with the slide back if you pull the trigger, its smooth as can be no noise. But, if you close the slide, magazine out and pull the trigger you hear a grinding noise towards the back of the slide. Any one else have this issue? Is it normal? Do I need to take the firing pin out and clean that? I once saw a video on YouTube of someone with the same issue. Any thoughts?

Yes, they are a bit noisy, especially at first.
I spray out the action with CRC silicone to clean it. The slight amount of dry silicone powder residue is all you need on the plastic parts. Lube the rest per the factory manual. Don't slop oil in it in an attempt to make it quieter, or you will shorty have a gunked up mess.

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Science plus Art

When I bought my first M&P, I didn't noticed anything wrong, loved the gun and shot it very accurately. As I found the BB's and read more about the M&P's I discovered that I had this terrible 10lb trigger, so I purchased the APEX sear and it helped to lower my trigger pull, I shot about the same but it made all the naysayers on line feel better. Then one day I came across a video on Youtube where some guy was ranting about his M&P trigger being so bad he had to get rid of his gun. He made a video of the gritty sounding trigger as he pulled it. By this time I had 4 M&P's and never noticed the gritty feel and sound he was talking about so I checked them and noticed my 40c sounded and felt similar, so I inspected my gun and figured out the striker assembly area was the culprit. Just like you, with the slide locked back, the trigger pull was smooth and quiet, with the slide moved forward, I could feel and hear it. I had already installed the sear and a few springs from my APEX DCEAK kit, but not the striker safety plunger and spring. So I installed the new striker plunger and spring from the APEX kit, and just like that, my trigger pull was as smooth as glass and quiet as a mouse... and I still shoot just as good, but that guy on Youtube should be happy, caused I fixed my gun..

Hope this helps,

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Jack C

I have no clue how to do what you explained. All I know about my gun is how to shoot it how to clean it "the field stripped way" and load it. Are you saying that I need to replace something? Or do I just need to remove the firing pin and clean that. Or just leave it alone and continue on my way?

M&P's do not have a firing pin, they have a Striker.

To eliminate the grittiness you're experiencing, you need to remove the striker safety plunger, clean and radius the corner on the plunger.

Here's a great link...

S&W M&P Trigger Job

Since you know how to do Youtube, just do a search for Apex DCEAK install and the videos will show you how to install any of the parts that APEX makes for our M&P's, it all very simple and relatively cheap to me.

I like the link Russ supplied, looked at that when I got my first M&P, just didn't want to spend the time nor did I want to modify my original parts. That's why I purchased 4 kits from Apex for all of my M&P's, I saved all my parts and can easily reinstall if I ever need to. One thing to remember, if you modify any parts and ever have to send your gun in for warrantee work, most likely your modified parts will be replaced with factory new parts, if you didn't void your warrantee.

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Jack C

From your description, it would seem that you need to clean your striker, striker tunnel and striker safety plunger area. I'll also point out that there's a debris "drain" at the front of the striker tunnel that leads to the bottom of the slide that probably also needs cleaned.

To find the last, look at the bottom of the slide. About 1/8 inch back of the breech face, you'll see what looks like (and is) a small hole. Clean this with a paper clip or something similar with the striker removed. Make sure you get all the crud out of the stiker tunnel afterwards. Note: the purpose of the "drain" is to allow any metal particles (or other crud) that may enter the striker tunnel through the firing pin hole in the breech to exit the tunnel and not interfere with operation. It's a very nice touch.

An awful lot of 'lousy trigger' complaints are simply inadequate cleaning and incorrect lubrication. That's an observation, not personal criticism.