Corrected, it's been a while. All of these pistols have various names for marketing reasons and it gets confusing. Anyway...The FBI did not issue or adopt the S&W M&P 40. The FBI did adopt the 40 S&W and issued Glocks chambered in said calibre.
They did however issue S&W M&P revolvers at one time (S&W model 10)
Firearms of the FBI: A Historical Overview - Inside Safariland
From revolvers to semi-autos, here’s how decades of innovation have changed FBI firearms and what that means for today’s agents.inside.safariland.com
-
If you are having trouble changng your password please click here for help.
Help an ignorant person - how can I pistol discharge with a finger on the trigger? MP40 in particular.
- Thread starter shootstraight78
- Start date
Let me re-focus the conversation on to my .40 S&W. Obviously, no matter how hard anyone tries there is no way it's going to go bang if there is no round in the chamber. Let's move past that. This pistol is a Springfield XD with a grip and trigger safety.
My original question involved how the grip and trigger safety worked in conjunction. If you don't know the pistol, that's fine. I'll poke around a more specific site to understand how this specific safety system works. It's more of an "engineer wants to know" question.
Meanwhile, since the Sig 320 is having it's issues, it appears that the Barret sniper rifle is having issues as well.... but let's not go there.
My original question involved how the grip and trigger safety worked in conjunction. If you don't know the pistol, that's fine. I'll poke around a more specific site to understand how this specific safety system works. It's more of an "engineer wants to know" question.
Meanwhile, since the Sig 320 is having it's issues, it appears that the Barret sniper rifle is having issues as well.... but let's not go there.
There are schematics available that explain and illustrate passive and direct safeties, and how they work. I’d start there.
I got a spring kit and replaced two springs.. That's pretty much it. I quickly put em back in but that was in the 1990s so many many years ago. Lesson learned.......Don't **** with glock mechanics.
For what it's worth, the OP wanted to know how a particular firearm could discharge when dropped. Different guns have different mechanisms and what might cause an ND when dropped could depend very much on the mechanism. So knowing for sure what model is being discussed is important. That said, for a gun to fire when dropped comes down to a couple of causes. And they're pretty simple.
You then follow it up by saying "Let me re-focus the conversation on to my .40 S&W" and THEN say "This pistol is a Springfield XD". It seems you're confused. So I'll answer what you seem to be asking with some general observations.
One absolute prerequisite of an ND - as you note - would be that there's a live cartridge in the chamber. If there isn't, that gun can't ND. Period. It's a non-issue.
But.
Almost all modern handguns are designed with multiple safety mechanisms that stop the firing pin from moving unless the handgun is being used in a correct manner - i.e. in your hand, the trigger being depressed with a finger or similar. Typically these will include a firing-pin block or a transfer bar which stop the ass-end of the firing pin being struck when you don't want it to.
Many striker-fired guns have a 'dingus' in the trigger which immobilize the trigger unless there's pressure on the face of it (as would be the case if you held the gun and put your finger on it). Not all do. Case in point, the P320, and that was one of the causes of the original P320 drop safety issue. The trigger was heavy enough that if you dropped it on the beavertail or the back of the gun in general, the momentum of the trigger was sufficient to overcome the mechanical resistance of the firing mechanism and effectively "pulled" the trigger. That shouldn't be able to happen with a 'dingus' if it's working correctly.
That said, all these mechanisms are reliant on the mechanism being clean and well-maintained - and any wear anywhere in the mechanism can compromise the safety.
As
wolfmanrogers
says though, the specifics of how an M&P 40 works - specifically your version of the M&P 40 - is going to be best learned via something like this:
Safety & Instruction Manual - M&P Shield and M&P Shield M2.0
Pages 17 thru 21.
If your interest is the Springfield XD, your best starting point is here.
Springfield Armory XD Manual
In general, however, the safeties of firearms are usually somewhat independent, so that a failure of one safety doesn't impact others. A good example of this is a firing pin block or transfer bar. They're actuated completely separately from magazine disconnects, grip safeties, trigger dinguses etc.
Being discrete subsystems of the mechanism, you might find these illuminating. Again, different guns have variations in implementation, but you're interested from an engineering point of view. You can always disassemble the gun and see.
1. General explanation of how a grip safety works: Video
2. General explanation of how a trigger dingus works: Video
3. General explanation of how a magazine disconnect safety works Video
4. General explanation of how a firing pin block safety works Video
You then follow it up by saying "Let me re-focus the conversation on to my .40 S&W" and THEN say "This pistol is a Springfield XD". It seems you're confused. So I'll answer what you seem to be asking with some general observations.
One absolute prerequisite of an ND - as you note - would be that there's a live cartridge in the chamber. If there isn't, that gun can't ND. Period. It's a non-issue.
But.
Almost all modern handguns are designed with multiple safety mechanisms that stop the firing pin from moving unless the handgun is being used in a correct manner - i.e. in your hand, the trigger being depressed with a finger or similar. Typically these will include a firing-pin block or a transfer bar which stop the ass-end of the firing pin being struck when you don't want it to.
Many striker-fired guns have a 'dingus' in the trigger which immobilize the trigger unless there's pressure on the face of it (as would be the case if you held the gun and put your finger on it). Not all do. Case in point, the P320, and that was one of the causes of the original P320 drop safety issue. The trigger was heavy enough that if you dropped it on the beavertail or the back of the gun in general, the momentum of the trigger was sufficient to overcome the mechanical resistance of the firing mechanism and effectively "pulled" the trigger. That shouldn't be able to happen with a 'dingus' if it's working correctly.
That said, all these mechanisms are reliant on the mechanism being clean and well-maintained - and any wear anywhere in the mechanism can compromise the safety.
As
wolfmanrogers
says though, the specifics of how an M&P 40 works - specifically your version of the M&P 40 - is going to be best learned via something like this:Safety & Instruction Manual - M&P Shield and M&P Shield M2.0
Pages 17 thru 21.
If your interest is the Springfield XD, your best starting point is here.
Springfield Armory XD Manual
In general, however, the safeties of firearms are usually somewhat independent, so that a failure of one safety doesn't impact others. A good example of this is a firing pin block or transfer bar. They're actuated completely separately from magazine disconnects, grip safeties, trigger dinguses etc.
Being discrete subsystems of the mechanism, you might find these illuminating. Again, different guns have variations in implementation, but you're interested from an engineering point of view. You can always disassemble the gun and see.
1. General explanation of how a grip safety works: Video
2. General explanation of how a trigger dingus works: Video
3. General explanation of how a magazine disconnect safety works Video
4. General explanation of how a firing pin block safety works Video
Thank you.For what it's worth, the OP wanted to know how a particular firearm could discharge when dropped. Different guns have different mechanisms and what might cause an ND when dropped could depend very much on the mechanism. So knowing for sure what model is being discussed is important. That said, for a gun to fire when dropped comes down to a couple of causes. And they're pretty simple.
You then follow it up by saying "Let me re-focus the conversation on to my .40 S&W" and THEN say "This pistol is a Springfield XD". It seems you're confused. So I'll answer what you seem to be asking with some general observations.
One absolute prerequisite of an ND - as you note - would be that there's a live cartridge in the chamber. If there isn't, that gun can't ND. Period. It's a non-issue.
But.
Almost all modern handguns are designed with multiple safety mechanisms that stop the firing pin from moving unless the handgun is being used in a correct manner - i.e. in your hand, the trigger being depressed with a finger or similar. Typically these will include a firing-pin block or a transfer bar which stop the ass-end of the firing pin being struck when you don't want it to.
Many striker-fired guns have a 'dingus' in the trigger which immobilize the trigger unless there's pressure on the face of it (as would be the case if you held the gun and put your finger on it). Not all do. Case in point, the P320, and that was one of the causes of the original P320 drop safety issue. The trigger was heavy enough that if you dropped it on the beavertail or the back of the gun in general, the momentum of the trigger was sufficient to overcome the mechanical resistance of the firing mechanism and effectively "pulled" the trigger. That shouldn't be able to happen with a 'dingus' if it's corking correctly.
That said, all these mechanisms are reliant on the mechanism being clean and well-maintained - and any wear anywhere in the mechanism can compromise the safety.
As
Safety & Instruction Manual - M&P Shield and M&P Shield M2.0
Pages 17 thru 21.
If your interest is the Springfield XD, your best starting point is here.
Springfield Armory XD Manual
In general, however, the safeties of firearms are usually somewhat independent, so that a failure of one safety doesn't impact others. A good example of this is a firing pin block or transfer bar. They're actuated completely separately from magazine disconnects, grip safeties, trigger dinguses etc.
When did the M&P 40 have a palm safety?
Never mind, finally got caught up on the comments
Never mind, finally got caught up on the comments
ANY mechanical devise can fail. All weapons should be considered loaded, and a constant effort to be treated as such should be mindset.
That being said, some models have better track records than others. All my handguns have hammers with built in guards to reduce the likelihood of an ND by dropping one.
But there is never a complete guarantee. Guns are dangerous if safety precautions are not adhered to, and life can be dangerous in and of itself.
You can reduce risk, but you can never remove risk all together.
That being said, some models have better track records than others. All my handguns have hammers with built in guards to reduce the likelihood of an ND by dropping one.
But there is never a complete guarantee. Guns are dangerous if safety precautions are not adhered to, and life can be dangerous in and of itself.
You can reduce risk, but you can never remove risk all together.
Treat all guns like they are a Sig P320
