keep trying.... 1mm in the calculations you provided represent the total distance over which the deceleration occurs, and this is not accurate for our purposes.... we are interested in that distance PLUS, more importantly, the distance over which the deceleration of the trigger occurs.... aka.... the length of the trigger pull before it breaks....
Shield recall
- Thread starter mailman390
- Start date
keep trying.... 1mm in the calculations you provided represent the total distance over which the deceleration occurs, and this is not accurate for our purposes.... we are interested in that distance PLUS, more importantly, the distance over which the deceleration of the trigger occurs.... aka.... the length of the trigger pull before it breaks....
if the inertia of the trigger is what the trigger safety is designed to protect against, the type of action would be irrelevant. Why don't revolver triggers have this problem with trigger inertia when dropped?
My disclaimer is that I've never disassembled a pistol beyond what is required for cleaning per the manual.
Early calculations by someone assumed 100 g for the "trigger and trigger bar assembly." Do they move in the same direction? When we look at the effects of inertia on the "trigger," should it be only the piece of plastic the finger pulls or that and the trigger bar?
If it is only that piece of plastic, what is its mass? A few grams? If so, the huge acceleration values don't translate into huge forces.
The base units of F=ma are Newtons, kilograms, and m/s^2. If you crunch the numbers on the plastic trigger where it has a mass of 1-5 grams, that is 0.001-0.005 kg.
The ~14,500 m/s^2 acceleration (~1,500 g's) from the conservation of energy equation looked fine to me. The post that explained it took me down memory lane! Anyway...
F=m x a
F= 0.005 g x 14,500 m/s^2 = 72.5 N.
(1 lb = 4.448 N)
Force due to inertia on a 5 gram trigger is 72.5 N or 16.3 lbs. The trigger may have less mass than 5 grams.
The statement elsewhere about forces being vectors was an excellent point. The direction must line up exactly for 100% of the force to be realized.
Don't forget my disclaimer above! The trigger bar mass may need to be included, but I suspect vectors are required if you must take it into effect.
As I've stated before, I know S&W did not design this safety for no reason, but I don't think it's as likely to be needed as the huge (though correct) number of "1,500 g's" implies.
There is something else that could be behind the need of the safety: "safety factors." By applying an engineering SF of 2.0 (or whatever) in their design, S&W may have then said, "Yeah, we need to include an inertia safety on the trigger."
Though there is a lot of disagreement here, there is some good thinking coming from all sides. Motomed makes a good point. The acceleration of 1,500 g's is or is nearly instantaneous. The trigger is not going to reach the break over point instantly.
Many thanks to Rastoff's friend's input, too. And the poster that mentioned in vectors.
Early calculations by someone assumed 100 g for the "trigger and trigger bar assembly." Do they move in the same direction? When we look at the effects of inertia on the "trigger," should it be only the piece of plastic the finger pulls or that and the trigger bar?
If it is only that piece of plastic, what is its mass? A few grams? If so, the huge acceleration values don't translate into huge forces.
The base units of F=ma are Newtons, kilograms, and m/s^2. If you crunch the numbers on the plastic trigger where it has a mass of 1-5 grams, that is 0.001-0.005 kg.
The ~14,500 m/s^2 acceleration (~1,500 g's) from the conservation of energy equation looked fine to me. The post that explained it took me down memory lane! Anyway...
F=m x a
F= 0.005 g x 14,500 m/s^2 = 72.5 N.
(1 lb = 4.448 N)
Force due to inertia on a 5 gram trigger is 72.5 N or 16.3 lbs. The trigger may have less mass than 5 grams.
The statement elsewhere about forces being vectors was an excellent point. The direction must line up exactly for 100% of the force to be realized.
Don't forget my disclaimer above! The trigger bar mass may need to be included, but I suspect vectors are required if you must take it into effect.
As I've stated before, I know S&W did not design this safety for no reason, but I don't think it's as likely to be needed as the huge (though correct) number of "1,500 g's" implies.
There is something else that could be behind the need of the safety: "safety factors." By applying an engineering SF of 2.0 (or whatever) in their design, S&W may have then said, "Yeah, we need to include an inertia safety on the trigger."
Though there is a lot of disagreement here, there is some good thinking coming from all sides. Motomed makes a good point. The acceleration of 1,500 g's is or is nearly instantaneous. The trigger is not going to reach the break over point instantly.
Many thanks to Rastoff's friend's input, too. And the poster that mentioned in vectors.
Not quite... The action of a true DAO revolver trigger and the action of Striker Fire pistol are apples and oranges (or Apples and PCs).
While some manufacturers advertise their Striker Fire system as being DAO, they are all much closer to being a SA trigger than that of a revolver.
Compare these two visual examples. If a picture is worth 1000 words, then the 2 links below speak volumes:
Glock Pistol Animation
Modern Revolver Animation
Unfortunately, the Glock 'Safe Action' illustration is the only Striker Fire example they show, but it's pretty close to the M&P system.
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Inertia Trigger is not concerned with any of this, and is only concerned with how much force it needs to generate to go bang. a revolver with a 6lb trigger pull of x length would be just as susceptible to inertia drop trigger as a striker fire pistol with a 6lb trigger pull of x length. what mechanisms generate that force or resistance is irrelevant to Inertia Trigger.
My 12 year old daughter can't pull back a double action trigger on a revolver. You could drop it from the moon and that 100 lb trigger isn't going anywhere upon impact.
Russ
jframe
Member
This thread has deteriorated from a gun related issue into one dealing with physics. Thought I might find new info on the safety alert, but it just ended up making my head hurt with facts and figures. Hell, it's hard enough for this boy to make change, much less understand all those theorems.
MrJT
US Veteran
I'm glad they described the issue well and explained how to test your trigger. I tested mine as soon as I read the announcement on their website.
The only gripe I have about the Safety Alert, is that they didn't email those who registered their pistols and supplied them with an email address. Since most of us don't visit the S&W site daily, we basically had to find out via the Forums.
Other than that... Very well presented description of the problem and how to test ours. Pretty Good Job, over-all.
Other than that... Very well presented description of the problem and how to test ours. Pretty Good Job, over-all.
Soldiernurse
US Veteran
My Shield trigger is working properly, per SA Website directions.
However, my XDs45 S# is on the recall roster.
However, my XDs45 S# is on the recall roster.
kodiakpb
Member
- Joined
- Jul 3, 2012
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The only gripe I have about the Safety Alert, is that they didn't email those who registered their pistols and supplied them with an email address. Since most of us don't visit the S&W site daily, we basically had to find out via the Forums.
Other than that... Very well presented description of the problem and how to test ours. Pretty Good Job, over-all.
Agreed.....
Wow, I leave for a week and a thread turns to physics!!! Yea!! I like physics!! 
I will go back and read the posts, sounds exciting with vectors and g-forces, and even centrifugal force being tossed under the bus. I remember a class that discounted centrifugal force back in high school. By the time college rolled around it was a given that no such thing existed. I never had the heart to tell my centrifuges that they were mis-named.
Anyway, my three Shields all pass the test. One was built in 2012, and the others in 2013.
My question in light of the physics being discussed, and maybe this has been covered:
Is the trigger evaluation a good enough indication of function? Is there more inside that may be wrong?
.
I will go back and read the posts, sounds exciting with vectors and g-forces, and even centrifugal force being tossed under the bus. I remember a class that discounted centrifugal force back in high school. By the time college rolled around it was a given that no such thing existed. I never had the heart to tell my centrifuges that they were mis-named.
Anyway, my three Shields all pass the test. One was built in 2012, and the others in 2013.
My question in light of the physics being discussed, and maybe this has been covered:
Is the trigger evaluation a good enough indication of function? Is there more inside that may be wrong?
.
SmurfHunter
Member
The only gripe I have about the Safety Alert, is that they didn't email those who registered their pistols and supplied them with an email address. Since most of us don't visit the S&W site daily, we basically had to find out via the Forums.
Other than that... Very well presented description of the problem and how to test ours. Pretty Good Job, over-all.
Couldn't agree more.
charliehustle77
Member
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Rastoff
US Veteran
The short answer is no. At least not as far as dropping the gun in concerned. If the trigger safety is working properly, it won't allow any of the internal trigger parts to move.
Let's look at the total safety system:
If the gun lands in the proper attitude to allow the sear to fall on its own, that would be with force toward the grip, the striker block will stay in place and stop the striker from hitting the primer.
If the gun lands in the proper attitude to disable the striker block, towards the slide, then the sear will stay in place and not allow the striker to hit the primer.
If the gun lands on the muzzle, both the sear and striker block will stay in place thus keeping the striker from hitting the primer.
This is a very safe gun.
zzzippper
Member
Not sure if this has been posted yet. It is from S&W and details the potential problem and how to check for it:
https://www.smith-wesson.com/webapp...buffer&utm_medium=twitter&utm_campaign=Buffer
https://www.smith-wesson.com/webapp...buffer&utm_medium=twitter&utm_campaign=Buffer
Edmo
US Veteran
Now that we've lived through almost 300 hand-ringing posts over: The Shield recall/safety alert was obviously started by a troll; the word play of recall vs safety alert; and a physics lessons on the inertia of plastic, here is my take...
There is a S&W RECALL over the plastic tab on the trigger?? I filed mine off months ago thinking it was excess plastic left over from manufacturing!
The rumor (read: my rumor) is S&W will install a magazine safety on any returned Shields. Either that, or they will install Apex trigger parts... I don't "recall" which option I heard they were going to perform. 
Now reality... Take the 30 seconds and check your Shields. Most will be good and those that aren't can easily be sent back for a quick turn-around. For those Shields which check out "good", get out and shoot them! Case closed.
Edmo
There is a S&W RECALL over the plastic tab on the trigger?? I filed mine off months ago thinking it was excess plastic left over from manufacturing!
The rumor (read: my rumor) is S&W will install a magazine safety on any returned Shields.
Either that, or they will install Apex trigger parts... I don't "recall" which option I heard they were going to perform. Now reality... Take the 30 seconds and check your Shields. Most will be good and those that aren't can easily be sent back for a quick turn-around. For those Shields which check out "good", get out and shoot them! Case closed.
Edmo
I actually found out through a local dun dealer, who belongs to our gun club. He posted it on a Yahoo group. Geez, they certainly collect enough information when you buy a gun, you'd think they could actually use for the gun owner's benefit in times like this.
Just like insurance... Everyone wants you to buy through them... Nobody wants to pay out when you have a claim.
They received mine on 9-6. When I called on 9-3 they told me 5-7 business days to fix. When I called last Friday 9-13 they said its now 7-10 business days. Maybe next week it will be 10-13 days.
The part I have a hard time with is that they keep telling me that the tracking number used to ship will be reused when they return the firearm.
I didn't think you could use the same label and tracking number. This is information I am getting from S&W.
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SMMAssociates
Member
betoesca:
UPS (or is it FedEx?) DOES reuse tracking numbers, but not for a while. IMHO, it'd be a little insane for S&W to reuse any numbers that they assign in less than six months (or longer).
Regards,
UPS (or is it FedEx?) DOES reuse tracking numbers, but not for a while. IMHO, it'd be a little insane for S&W to reuse any numbers that they assign in less than six months (or longer).
Regards,
Lee in Quartzsite
Member
I agree. What good does it do to send in a warranty card with your contact information if S&W doesn't mail out the Safety Alert? I have a neighbor who has 2 Shields and no computer. The only way he learned about the notice was from me...both of his passed. S&W needs to improve their customer support because not everyone is computer savvy or visits gun forums.
I had it shipped 9/3 and it arrived at S&W on 9/5. I got it back on 9/13.
No, it was different.
I was told the very same thing.
I got my Shield back today. As Storm40 stated they do not use the same tracking number.
I shipped it on 9/3 they received it on 9/6 and I got it today on 9/18. That's 8 business days.
I called the number for the Shield recall earlier today and let them know they don't reuse tracking numbers and the girl told me to call the same number I had just dialed. I don't even think they are anywhere near S&W. But I did call 1-800-331-0852. I told the operator I wanted to return a weapon and the next person I spoke to looked up my gun using the serial number and told me it would deliver today.
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I shipped it on 9/3 they received it on 9/6 and I got it today on 9/18. That's 8 business days.
I called the number for the Shield recall earlier today and let them know they don't reuse tracking numbers and the girl told me to call the same number I had just dialed. I don't even think they are anywhere near S&W. But I did call 1-800-331-0852. I told the operator I wanted to return a weapon and the next person I spoke to looked up my gun using the serial number and told me it would deliver today.
Sent from my iPhone using Tapatalk 2
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