To make a long story short, I've had this m&p since late 2007 and, off and on, it's been a problem child for me ever since I purchased it. I've sought (and received) help from S&W several times already for such things as light primer strikes and dead trigger issues and I now seem to be having some failure to feed issues with it and my patience is running out trying to babysit this thing. I've changed out strikers in this gun twice and, in 2015, I had to fix a dead trigger issue in it and, quite frankly, I have begun to lose confidence in this gun. It's frustrating because my glock seems to run just fine with both my reloaded ammo and factory ammo but this s&w just keeps giving me one headache after another. 

Today, I was shooting some of my own reloaded .40 caliber 180 fmj reloads (which have shot just fine in the past out of my nearly stock glock 22) and I had two light primer strikes along with several failures to feed. I figure I would clean it up (even though it doesn't look all that dirty right now), lube it up and try shooting some factory ammo out of it tomorrow and see if it's a reloaded ammo problem or a gun issue. If it's a gun issue again then I will likely seek help from s&w one more time and then sell it and use this opportunity to convert over to either all glocks (except for my two 1911's) or switch over to using 9mm m&p's.

Have you actually returned it to S&W for inspection/repair? If so, and it is still having issues, it would be gone if it was my gun. Knock on wood, I have had very good fortune with the firearms I have owned, but if the manufacturer is unable to repair it to working order, I would be asking about a replacement or I would part with it. If I recall correctly, didn't the early models have issues with dead trigger/light primer strikes?

Mine is an earlier model and it did have some striker related, light primer strike, issues which, for the most part, have now been solved (after going through two different striker replacements, that is). It did have two light primer strikes earlier today but I still haven't ruled out that my latest problems aren't primarily an ammo issue first. Today I only shot my reloads through the gun but tomorrow I will try some factory ammo and see what happens.

The gun has never been sent into s&w for repair but I have talked with s&w reps both on the phone and on their website to solve problems in the past. My issue isn't with their customer service because that's been pretty good for me, all in all. I do, however, have a problem with my particular guns reliability as it just isn't up to par to other guns that I currently own. I own two 1911's and one glock and they have all been far more reliable and consistent for me than my m&p ever has.

Does your M&P have issues with factory ammo as well?

Also, depending on the amount of ammo you have fired through your M&P, have you ever replaced your recoil spring and magazine springs, by chance?

It's had issues with factory ammo in the past but I only fired reloaded ammo earlier this afternoon.

I've had the gun since around october 2007 and, in that time, I've probably fired less than 1500 rounds through it. The total round count through it is probably closer to 1000 rounds than it is 1500.

I had an issue with my first duty M&P40 with failures to feed/go completely into battery. For me it was a worn out recoil spring assembly (roughly 7k rounds on it). Once the RSA was changed out; I didnt have any more issues with it.

It rained pretty heavy here today and we are due more rain tomorrow so my next best day to do a retest will be sometime thursday.

My plan is to try a small assortment of factory and reloaded ammo through both my m&p and glock and see what happens. If it's an ammo issue then the glock should have problems, too. However, if it's just a gun issue then the glock should be okay. If it does turn out to be a gun issue then I will contact smith & wesson again and send it back to them to fix. I may or may not get rid of it depending on how all of that turns out when all is said and done.

I really prefer the ergonomics of the m&p over those of the glock but I only want a gun that I can absolutely trust and that's simply not the case with my m&p right now (and, for all practical purposes, that hasn't really been the case since I purchased the gun way back in 2007). I've been more than patient with it while trying to get it to work through its various issues and, quite frankly, my patience has begun to wear out now. It's time for me to get it to work, once and for all, or it's time for me to ditch it and continue to go with glocks or go to the sig P320.

Junk it.  Unreliable guns are worthtless except as a paper weight.  There are brands that tend to work all the time.  Try another.  (I note you have a Glock.  Use it.)  

Money isn't worth the frustration.  A gun gotta work.  Any other feature is an extra.

(Yes, I like Glocks.)

I've had a similar issue with my reloads before that had hiccups in the S&W but not my Glock. Turned out when I ran out of bullets reloading I opened another pack but it was another MFG and my OAL changed to just outside the recommended length. Stupid of me not to check, but for whatever reason the Glock didn't care.

Easy fix, I just went back and re-seated everything at the proper length. Hopefully that may be the case here.

Had similar issues with my M&P 9MM.  An Apex CAEK kit fixed it for about a year or so and then it started again.  Based on some info/suggestions from a guy on the M&P forum (most there blamed it on primers, my reloads, etc.) I looked into both the dead trigger and light strike issues (timing), made some changes and it seemed to be trouble free for 350 rounds.  By then I'd already switched to a CZ P07 and it was perfect.  The M&P went into the gun safe along with the second M&P I'd bought (tumbled the same .357 SIG reloads my Glock shot just fine).

I'm a CZ owner/shooter now.

The best striker fired pistol I've owned was the XDM pistols.  100% reliable, more accurate than the Glock or M&Ps.  I just got more and more of an uncomfortable feeling with them at the time and moved to the M&Ps (felt great in my hand, really good - most comfortable gun I'd held since my 1911's).

I'm "off" striker fired guns now that I've seen how well the CZ's shoot but CZ is coming out with a new striker fired plastic framed pistol.