The question of the value or how the thumb safety works comes up now and then. So, here's the straight skinny...

The thumb safety on all the M&P pistols simply blocks trigger movement. Here's how it does it:

When the thumb safety is on, the tab indicated by the red arrow, blocks the trigger from moving by blocking the bend in the trigger bar indicated by the green arrow.

When the thumb safety is off, like this:

That tab just drops down out of the way.


That's it. That's all it does. Sorry it's not more exciting, but it really is that simple. It has no connection to the sear or striker at all. It just blocks trigger movement.

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Freedom isn't free.

If you're implying that this negates the value of a thumb safety to those who want one, I fail to see how. It works, that's all that matters.

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Lounge Lizard Extraordinaire

I think what the OP is saying is that it is a simple mechanical block that is unlikely to cause a problem since it doesn't really do anything other than block the movement of the trigger bar when engaged.

If you like it (which I do and it was a selling point on the Shield for me) then use it. If you don't like it then don't use it.

Jeff

The OP contained no implications at all. It only demonstrates how the thumb safety works. Whether or not anyone likes it is up to them.

Clearly some like it and some don't. Thus the reason for the many variants.

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Freedom isn't free.

It is nice that the OP was willing to take time and spend effort to create the visuals.

Many, like me, are not inclined to make an unsolicited effort to help others. I'm just lazy. Can't speak for anyone else.

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Incoming fire has right of way

what is the suggested spot to cut the right side safety lever off? Gonna make room for a crimson trace grip laser.

Thanks for the little pictorial on the thumb safety. To paraphrase Forrest Gump, "simple is as simple does..."
I like having a safety that helps prevent something very unpleasant when loading and unloading the pistol.

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NRA Life Member

Yep.
Exactly.
I'm always amazed when so-called experts say they don't/won't own a particular gun because it has a safety "...and doesn't need it."
I've been a confirmed Glock guy for 20 years and don't feel I need a manual safety on a properly-designed striker-fired gun.
Having said that, I've gotten used to the Shield's safety quickly. I only engage it when I'm holstering it, essentially, but that added measure ain't all bad.
Thanks to the OP for the pics & explanation on how the safety works!

the only external safety i can stand is the 1911 thumb safety.

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My mind is my own church.

First, thank you for posting how the safety works. I did not know. I appreciate your time.

I cut mine off right at the lever as per some suggestions in this forum. M&P 40c. It seems to work just fine. I believe one of the pieces to fill the hole from S&W would fit, even though it does not look like it in the photo. I didn't bother with it. No snags or hang ups, and the gun shoots just fine.

Perfectly simple. I like it and use it when reholstering blindly at the small of my back; after holstered it gets flicked off.

Thank you for the post, always wondered how it worked (don't have one).

Will

Your username suggests you shouldn't be asking questions about cutting off a safety device. Common sense would dictate buying an M&P that didn't have one.

I, however, come from 1911s and all my M&P's have thumb safeties...I wouldn't have a striker-fired pistol without one.

Yeah, it is a rather simple & elegant design, isn't it?

An advantage to the thumb safety of the M&P is that the slide can be run (manually retracted) when it's engaged, unlike the thumb safety lock design used in the 1911.

Some owners of 1911's have complained that the resistance in operating the M&P thumb safety lever is too much lighter than that of their favorite 1911. While S&W doesn't offer or apparently condone modification of their lever to increase the resistance needed to raise or lower the lever, I studied it a bit and was able to subtly change a couple engagement spots (angles) on the lever body to increase the amount of force needed to move the lever past the plunger from either position.

Naturally, doing this risks ruining a lever body/assembly, and it's not easy to get replacements outside of being an armorer. FWIW, I also discovered there's a point in changing one of the angles where it becomes virtually impossible to ever again move a lever.

I've done the modification for a couple 1911 guys who like owning & using M&P 45's, but only after receiving authorization to do so from the agency's FTU supervisor (so the modification would be covered by the agency, and not just something for which I'd be responsible).

I've tried a couple later production M&P's that came with the thumb safety option, and they seemed to have some better resistance to the lever being moved, so maybe (dunno) S&W has made some subtle revision ... or, maybe there's a wider range of tolerance stack among the guns than I'd previously noticed.

The fact that the M&P safety lever rests in a different position than that of a 1911 probably gives more 1911 users more indigestion than anything else.

Considering the manual safety option was originally only developed for the anticipated military pistol program anticipated in '05 (as a required spec feature), it reportedly caught S&W engineers by surprise when public clamor arose for the manual safety to be incorporated throughout the commercial model line.

It eventually necessitated some frame design changes (frame cuts & plugs), as well as which configuration of the sear housing block would become the "standard" sear housing block configuration.

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Ret LE Firearms inst & armorer

Thanks Rastoff.

I like the safety and use it the same as with a 1911, although it isn't nearly as easy to manipulate, as least for me.

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USAF, 69-92
Vietnam, 72-73

On face value, that make good sense. However, if one wants a thumb safety, AND the Crimson Trace Laser Grips, the thumb safety lever on the right side of the firearm has to be removed. There is no way around it.

While there are other options for laser sites, the Crimson Trace Grip lasers work much better for me. First, I can use them with most any holster. But most importantly, for me, when the weapon is unholstered, it is on, which allows me to keep my focus on the target. No reaching for a button or switch.

In the end, this simple and safe modification allows me to retain the thumb safety on the firearm, and still use the Crimson Trace Laser Grips, something Smith and Wesson does not provide on a factory M&P 40c.

Agreed (with your first sentence!). Thanks, OP! Good to see a visualization of the safety.

I have been kicking around the idea of getting ct laser grip for my 9c, but have always been hesitant to do so because I have always thought that my index finger (when not in the trigger guard area) would just block the laser due to it (my finger) being along the frame. Whereas this would not be the case in a f/s m&p (longer grip). Am I wrong to think this?

I have a 1911 and an M&p 40c with the thumb safety and to me they are identical.Having owned the 1911 for several years before the M&P I thought it was a good idea.It works for me and I am more comfortable with the thumb safety but I can't understand the big difference between the two.

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I'm just here for the guns.

I started this so, I'll hijack it if I want.

My opinion on lasers is that they're great for practice and have a niche place in self-defense, but generally would not put one on my gun.
You are not completely wrong, but there's more to the story.

I teach that when your finger is not on the trigger, it should be on the reference point. This is a place outside the trigger guard and above the trigger, along the frame of the gun. Like this:


When viewed from the right side it looks like this:


If you look closely, you can just barely see my trigger finger on the other side. Using the reference point has a couple of good points; it ensures you're trigger finger is nowhere near the trigger and it ensures everyone around you can see that you're not on the trigger. It makes everyone involved safer.

OK, with that in mind, it's easy to see that a right hand shooter will always block the laser with his trigger finger when not on the trigger. This is actually a good thing. Even though the laser is on because of the grip switch, you're not a target because you've blocked the laser. A simple move of the trigger finger allows the laser to shine on the target. This way the element of surprise is maintained and the advantage of the laser in low light is still available.

A left hand shooter cannot use a CT Grip laser.

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Freedom isn't free.

Ya, sorry for jacking your thread. Thanks for the input, guess there are advantages to blocking that laser