I'd be reluctant to call it anything like a "known problem", myself.
The slide stop assemblies are probably stamped and produced by one of the vendors S&W uses, and like any other assembly or part produced in batches & production runs, there may be some turned out now and again that fall on the wrong end of whatever the required S&W specifications may be, or some made on a machine that isn't properly calibrated at some point in time.
Kind of like how one of the machines that makes the Glock frame rail insert fixtures wasn't properly calibrated for a short time, and a small (comparatively) number of rear frame rails across their model line could be subject to having the left rail snap off. We were told in one armorer class that it only affected a small number of production, less than 1% (or only several thousand guns), and were mostly con fined to the E-series production. It can happen.
I've not had personal experience with such a problem with my own M&P's (admittedly only over the course of shooting upwards of 6K rounds), nor have I come across such a slide stop assembly breakage among the many other M&P's which I help support (and occasionally shoot) belonging to other folks.
If I do, I'll replace the affected slide stop lever assembly (much as I would with any other damaged, worn or unknowingly defective part). If I weren't an armorer for the M&P's, I'd use the company's excellent lifetime service support (with free shipping both ways).
As far as the particular cs rep expressing he's not heard of that occurring? Well, that wouldn't surprise me. The company has lots of folks who answer the main CS phone bank, and they make a lot of products, not all of which are firearms (let alone M&P pistols), and which generate a lot of calls every day.
FWIW, I've had the opportunity to meet a fair number of M&P owners, users & armorers, as well as discuss them with reps and the cdesignated LE cs contact (who shoots a M&P for occasional competition). Haven't heard of an "epidemic" of broken slide stop assembly tabs ... yet.
Kind of like how I heard online of the small plastic pins walking out of the triggers a couple years ago in some unknown number of M&P's. When I called back to check into it (to see if I needed to order more trigger bars), I was told that a few guns had exhibited the condition at an agency which was using over 1,500 M&P 40's (since '07). It was only discovered when some company field armorers stopped by to check up on their agency customer, and it was noticed that a few of the guns being used for quals had trigger (hinge) pins that had shifted. No functioning problems were occurring, and it had only happened to a handful of the guns they checked. I was told it was conjectured that it might have been a "one time" tolerance glitch with the itty bitty plastic pins (vendor supplied, although the trigger bar assemblies are assembled at S&W), and since it hadn't surfaced elsewhere in guns of a similar 2-year old production period, or newer, it was probably one of those things for which they'll really know what happened. They said they'd be pleased to replace any trigger bars that ever exhibited a similar condition, though.
And to avoid the appearance of just picking on S&W and the relatively new M&P, a little while back I heard from another Glock armorer about a similar "walking" trigger pin in some agency's .40's ... and the armorer said the Glock folks who came to the agency were suitably puzzled, and I was told they said they'd never heard of such a thing.
Parts is parts ... and sometimes those parts might not be turned out at the optimal end of the ideal, desired specifications.
Just look at the customer service driveways and see folks lined up for repairs, even at dealerships for the best known and most respected brands.
Slide Stop Broken
Linear Mode
