How important is the Smith and Wesson "hammer block safety"???
- Thread starter lharrell79
- Start date
I have seen a couple that needed repair, but never one that sheared.
Moreover, because the hammer pivot pin is supported at its side plate end (by a boss in the side plate), I strenuously doubt that even a hypothetical through shear at either the frame boss or the sideplate boss could result in a discharge of an uncocked Smith & Wesson revolver.
Moreover, because the hammer pivot pin is supported at its side plate end (by a boss in the side plate), I strenuously doubt that even a hypothetical through shear at either the frame boss or the sideplate boss could result in a discharge of an uncocked Smith & Wesson revolver.
RKG said:
Very interesting. I was skeptical, so I did perform your test (demo'd in the vid link above, btw), and confirmed the pencil did not, in fact, get hit even with the hammer block removed.
So, what's the point of the hammer block? It looks like very little rebound slide movement is needed to throw the hammer block into position, so it'll function even if/when the rebound slide gets sluggish. Once again, a backup to the rebound slide, then.
Mike Irwin
Staff
"The notion that the hammer block is necessary to prevent firing if a cocked hammer is somehow dropped without a finger on the trigger can be readily demonstrated to be false."
I don't think anyone has claimed that is the purpose of the hammer block in this thread, have they?
The hammer block is there to prevent an at-rest hammer from, in a worst case scenario, moving forward with enough force to fire a cartridge.
But, you're correct. If the trigger isn't held to the rear when the hammer is tripped, the rebound slide will intercept the hammer and prevent a cartridge from firing.
That may NOT be the case in the earliest Hand Ejectors, however, whose internal design differed significantly from today's guns.
I don't think anyone has claimed that is the purpose of the hammer block in this thread, have they?
The hammer block is there to prevent an at-rest hammer from, in a worst case scenario, moving forward with enough force to fire a cartridge.
But, you're correct. If the trigger isn't held to the rear when the hammer is tripped, the rebound slide will intercept the hammer and prevent a cartridge from firing.
That may NOT be the case in the earliest Hand Ejectors, however, whose internal design differed significantly from today's guns.
lharrell79
New member
Mike, in the video above of Miculek, it seems like that is what he's stating. That the hammer block would prevent a cocked firearm from firing, unless a finger was on the trigger. After watching the video, I thought that was the purpose of the hammer block. Now I'm left wondering again, what is the purpose?
I think we can all agree that S&W installed it to prevent accidental discharges. But what scenarios were they trying to prevent? After RKG's last post, I'm left thinking that it's only purpose is to prevent the following:
1.) You drop your revolver, the hammer shears off, and sends the firing pin home. The hammer block would prevent this in theory. Can anyone confirm that a hammer has ever sheared off? I'm thinking it would be next to impossible, unless the revolver were dropped from 20+ feet.
2.) Your hammer rebound slide gets stuck. Thus, if the hammer were cocked and dropped, the hammer would fall and the firing pin would find it's mark. Can anyone confirm the rebound slide actually sticking back?
Can anyone think of any other scenarios? When I originally started this thread, I was thinking along the same lines as RKG. That the hammer rebound slide pretty much prevents anything. I was initially thinking that maybe S&W installed these as a kneejerk reaction to the Navy accident. On a side note, my hammer block safety is in the mail, and should be here on Wed.
Lots of good discussion in this thread, lets keep it going.
I think we can all agree that S&W installed it to prevent accidental discharges. But what scenarios were they trying to prevent? After RKG's last post, I'm left thinking that it's only purpose is to prevent the following:
1.) You drop your revolver, the hammer shears off, and sends the firing pin home. The hammer block would prevent this in theory. Can anyone confirm that a hammer has ever sheared off? I'm thinking it would be next to impossible, unless the revolver were dropped from 20+ feet.
2.) Your hammer rebound slide gets stuck. Thus, if the hammer were cocked and dropped, the hammer would fall and the firing pin would find it's mark. Can anyone confirm the rebound slide actually sticking back?
Can anyone think of any other scenarios? When I originally started this thread, I was thinking along the same lines as RKG. That the hammer rebound slide pretty much prevents anything. I was initially thinking that maybe S&W installed these as a kneejerk reaction to the Navy accident. On a side note, my hammer block safety is in the mail, and should be here on Wed.
Lots of good discussion in this thread, lets keep it going.
So, should we all take our S&W's apart and remove that unnecessary block? Even if it were true that it could never possibly be necessary (and I am not sold on that idea) it does no harm. I was told by some people at S&W that they did succeed in breaking or shearing the hammer stud and collapsing the rebound slide, but maybe they were different folks than RKG spoke with.
But if S&W put in an unnecessary part, so did Colt, and their positive safety is a more expensive and complicated affair than the S&W safety. And I have seen a Colt hammer break completely off at the thin part; that did not happen because the hammer spur was hit or the gun dropped (it just broke in normal firing) the hammer block would have prevented firing when the rebound lever would have had no effect.
Jim
But if S&W put in an unnecessary part, so did Colt, and their positive safety is a more expensive and complicated affair than the S&W safety. And I have seen a Colt hammer break completely off at the thin part; that did not happen because the hammer spur was hit or the gun dropped (it just broke in normal firing) the hammer block would have prevented firing when the rebound lever would have had no effect.
Jim
James K said:
I've taken out the hammer block and the internal lock on my USPSA revolver (IDPA doesn't allow removal of the hammer block) simply because they're unnecessary (and the gun's converted to DAO to boot).
Outside of that, though, there's really no reason to remove it (or the lock, IMO).
A bit on the hammer block.
There is some confusion on this and I believe it is for a couple of reasons. Mainly because the S&W hammer block serves two functions and because the hammer block went through a number of changes.
I went and took a look at Roy Jink's "History of Smith and Wesson" and a couple of other books.
In WWII S&W looked to reduce the time it took to produce revolvers for the war effort. When it made the "Victory" revolver versions of the M&P it incorporated a new type hammer block. When the hammer was down the hammer block rested in a position that if dropped prevented the firing pin from hitting the primer. This type hammer block was removed from it's at rest position as the trigger was pulled and the hand raised to rotate the cyulinder. The hand cammed the hammer block into the sideplate. With the trigger pulled all the way to the rear the hammer was free to fall and strike the primer. The return of the hammer block into a position where it rested and prevented the hammer from striking the primer in the new Victory model was dependent on action of a small spring. Dirt or grease could impair it's ability to raise and block the hammer from hitting the primer or touching it if dropped.
Now the incident where the gun dropped on the ships deck did actually happen and the Navy did order S&W to re-examine it's modifications. S&W did just that, it revised the design. The revised guns were marked with a S prefix in front the V for "Victory Model". Following this new guns with the new hammer block in place received an S prefix before the serial number. The gun discharged with the hammer down. Nothing broke either before the gun fell or when it hit the ground. It was a small spring that was gummed up that caused the gun to fire.
The new hammer block was directly connected to the rebound slide and operated in a slot in the side plate it was mechanically forced into position by the action of the rebound slide. It was a stronger more robust action than any S&W had used before.
tipoc
There is some confusion on this and I believe it is for a couple of reasons. Mainly because the S&W hammer block serves two functions and because the hammer block went through a number of changes.
I went and took a look at Roy Jink's "History of Smith and Wesson" and a couple of other books.
In WWII S&W looked to reduce the time it took to produce revolvers for the war effort. When it made the "Victory" revolver versions of the M&P it incorporated a new type hammer block. When the hammer was down the hammer block rested in a position that if dropped prevented the firing pin from hitting the primer. This type hammer block was removed from it's at rest position as the trigger was pulled and the hand raised to rotate the cyulinder. The hand cammed the hammer block into the sideplate. With the trigger pulled all the way to the rear the hammer was free to fall and strike the primer. The return of the hammer block into a position where it rested and prevented the hammer from striking the primer in the new Victory model was dependent on action of a small spring. Dirt or grease could impair it's ability to raise and block the hammer from hitting the primer or touching it if dropped.
Now the incident where the gun dropped on the ships deck did actually happen and the Navy did order S&W to re-examine it's modifications. S&W did just that, it revised the design. The revised guns were marked with a S prefix in front the V for "Victory Model". Following this new guns with the new hammer block in place received an S prefix before the serial number. The gun discharged with the hammer down. Nothing broke either before the gun fell or when it hit the ground. It was a small spring that was gummed up that caused the gun to fire.
The new hammer block was directly connected to the rebound slide and operated in a slot in the side plate it was mechanically forced into position by the action of the rebound slide. It was a stronger more robust action than any S&W had used before.
tipoc
Driftwood Johnson
New member
tipoc:
If you go back and look at the photos in my earlier post, I have included a photo of the type of hammer block that failed in the Navy incident. There was no separate spring, the hammer block itself was a piece of spring steel.
If you go back and look at the photos in my earlier post, I have included a photo of the type of hammer block that failed in the Navy incident. There was no separate spring, the hammer block itself was a piece of spring steel.
Driftwood,
I see that the pic you have is from a 1926 gun. But as mentioned the hammer block design was altered when the "Victory" model of the M&P was introduced. I get this from Jinks Pg. 174-75. I borrowed from Jinks directly in the explanation I gave above. (Ezell pg. 508) says the same thing but seems to get it from Jinks
It was this hammer block, introduced in the Victory model with it's small spring that was eliminated beginning in 1944 and which led S&W to place the "S" prefix on the guns. The new safety was called the "slide action hammer block".
However, to be fair, Supica and Nahas in the 3rd edition of their book give a different description. They describe the safety as a shoulder on the rebound slide which was forced against a shoulder on the hammer. These shoulders kept the hammer nose off the cartridge in the down position. The force of a drop, or blow to the hammer, while it was in the down position, could shear the hammer pivot and cause the firing pin to strike the primer. They do not mention any spring which could be jammed with gunk.
About 40,000 revolvers were sent back to S&W for the modification.
According to Supica it is this design that is still in S&W revolvers. See page 142 of the Third edition of the Standard Catalog.
I'll ask about this over to the S&W forum, no doubt several essays written on the discrepancy.
At any rate the incident on the ship did occur. S&W did change the design. Since 1944 S&W revolvers have been safe to carry with a hammer down on a live round. The safety does not ruin the trigger pull (as many used to claim back in the 50s and 60s).
And most certainly it is important.
tipoc
I see that the pic you have is from a 1926 gun. But as mentioned the hammer block design was altered when the "Victory" model of the M&P was introduced. I get this from Jinks Pg. 174-75. I borrowed from Jinks directly in the explanation I gave above. (Ezell pg. 508) says the same thing but seems to get it from Jinks
It was this hammer block, introduced in the Victory model with it's small spring that was eliminated beginning in 1944 and which led S&W to place the "S" prefix on the guns. The new safety was called the "slide action hammer block".
However, to be fair, Supica and Nahas in the 3rd edition of their book give a different description. They describe the safety as a shoulder on the rebound slide which was forced against a shoulder on the hammer. These shoulders kept the hammer nose off the cartridge in the down position. The force of a drop, or blow to the hammer, while it was in the down position, could shear the hammer pivot and cause the firing pin to strike the primer. They do not mention any spring which could be jammed with gunk.
About 40,000 revolvers were sent back to S&W for the modification.
According to Supica it is this design that is still in S&W revolvers. See page 142 of the Third edition of the Standard Catalog.
I'll ask about this over to the S&W forum, no doubt several essays written on the discrepancy.
At any rate the incident on the ship did occur. S&W did change the design. Since 1944 S&W revolvers have been safe to carry with a hammer down on a live round. The safety does not ruin the trigger pull (as many used to claim back in the 50s and 60s).
And most certainly it is important.
tipoc
Mike Irwin
Staff
These are pictures of my circa 1920 Regulation Police .32 hammer block. I believe this is classified as the first generation hammer block.
It works not unlike the later "wing" hammer block, but uses more parts (a spring loaded pin in the sideplate along with the sprung hammer block itself).
In operating the hand pushed the pin back, which in turn withdrew the hammer block.
When the sideplate was released, the spring behind the pin pushed it into the small cutout in the hand and the hammer block was free to spring back into the "block" position.
At least that was the theory. When I got the Regulation Police in the 1980s, the hammer block was completely non functional becaue of all of the dried grease and oil. The pin was stuck in the rearward position, which kept the block cammed out of its rest position.
It took a good soaking to get everything freed up again.
It works not unlike the later "wing" hammer block, but uses more parts (a spring loaded pin in the sideplate along with the sprung hammer block itself).
In operating the hand pushed the pin back, which in turn withdrew the hammer block.
When the sideplate was released, the spring behind the pin pushed it into the small cutout in the hand and the hammer block was free to spring back into the "block" position.
At least that was the theory. When I got the Regulation Police in the 1980s, the hammer block was completely non functional becaue of all of the dried grease and oil. The pin was stuck in the rearward position, which kept the block cammed out of its rest position.
It took a good soaking to get everything freed up again.
lharrell79
New member
Tipoc, the question still remains, "What does the modern hammer block safety do?" I'm still left wondering? What scenarios is it meant to prevent?
Mike Irwin
Staff
"What does the modern hammer block safety do?" I'm still left wondering? What scenarios is it meant to prevent?"
Read post 15 again.
Jim perfectly explains the purpose of the hammer block.
I don't think any answer will be clearer than that.
This is what I said in post 24.
"The hammer block is there to prevent an at-rest hammer from, in a worst case scenario, moving forward with enough force to fire a cartridge."
That is the sole purpose of the hammer block.
Read post 15 again.
Jim perfectly explains the purpose of the hammer block.
I don't think any answer will be clearer than that.
This is what I said in post 24.
"The hammer block is there to prevent an at-rest hammer from, in a worst case scenario, moving forward with enough force to fire a cartridge."
That is the sole purpose of the hammer block.
lharrell79
New member
"IIRC, S&W did a lot of testing and found that the hollow rebound slide could be crushed by the hammer if the blow to the hammer were hard enough, or the hammer stud could be sheared off."
So the above is what the modern hammer block safety prevents? Does anyone have any links or information on the tests that were performed by the IIRC? I'm curious to see what the conditions were to shear the hammer or crush the rebound slide. The hammer and the rebound slide are very robust pieces in the modern S&W. I would think it would take an incredible amount of force to defeat either.
So the above is what the modern hammer block safety prevents? Does anyone have any links or information on the tests that were performed by the IIRC? I'm curious to see what the conditions were to shear the hammer or crush the rebound slide. The hammer and the rebound slide are very robust pieces in the modern S&W. I would think it would take an incredible amount of force to defeat either.
Mike Irwin
Staff
Parts look solid and durable until they're proven not to be due to improper manufacture, a flaw in the metal, a stroke of fate, etc.
I don't know of any information to definitively say exactly what failed to allow a dropped gun to fire, killing a sailor, but the act of redesigning the hammer block indicates that it was either a crushed rebound slide, a sheared hammer stud, or a broken hammer combined with the failure of the hammer block.
I don't know of any information to definitively say exactly what failed to allow a dropped gun to fire, killing a sailor, but the act of redesigning the hammer block indicates that it was either a crushed rebound slide, a sheared hammer stud, or a broken hammer combined with the failure of the hammer block.
Well, did it? So far as I can tell, no one has ever claimed to have examined that particular revolver, identified what part or parts failed, and how it was possible for it to discharge. When I was at Smith & Wesson, no one was able to come up with any such report, or even a hypothetical for the discharge scenario.
While it is true that the wing type hammer block could become inoperable on account of becoming glued into its raceway by dried lubricant, the dropped revolver should not have discharged even if the hammer block was non-functional (or missing altogether). In fact, it could not discharge unless something else failed. What? We don't know.
And the fact that we don't (and can't) know how that revolver supposedly failed is why some are skeptical that the incident ever happened at all.
I referred to two different sources for this out of a good many more. (I could pile them up by the door for ya if you'd like.) One is from S&W historian Roy Jinks and the other from the third edition of Supica and Nahas's "The Standard Catalog of Smith and Wesson". I cited the page numbers and you can pull 'em out and read for yourself.
I'm inclined to believe that Jinks version from 1977 is the "official" S&W version. It has S&W taking the lead on the redesign once they officially became aware of it.
Supica and Nahas (page 142 section on the Victory Model) report that after the incident on the ship's deck the Navy officially asked Springfield Armory to investigate the reasons for the discharge and come up with a better design. 40,000 guns were returned to S&W for refitting, an expensive retrofit during war time.
The retrofitted guns have a small "s" placed by the sideplate screw and a larger "S" placed before the serial number on the butt.
There are two different stories on how the accident occurred. One by Jinks in 1977 and one more recently by Supica and Nahas (Jinks had input into the Standard Catalog). But it did occur and led to a significant redesign.
Mike and Jim have explained what the hammer block does.
tipoc
Mike Irwin
Staff
The Navy said it did, and required a change to the gun. S&W said it did, and acquiesced to a change in design in the middle of a war.
The military as a whole said it did, and shipped about 40,000 revolvers BACK to S&W for the modification, again in the middle of war.
And finally, Roy Jinks, S&W's historian, says it did.
I'm convinced.
If you're really interested, a note dropped to Roy Jinks might open up S&W's files on the incident.
As for the mechanism of failure, Jim Keenen has already addressed the possibilities for that from a strictly gunsmithing point of view.
The military as a whole said it did, and shipped about 40,000 revolvers BACK to S&W for the modification, again in the middle of war.
And finally, Roy Jinks, S&W's historian, says it did.
I'm convinced.
If you're really interested, a note dropped to Roy Jinks might open up S&W's files on the incident.
As for the mechanism of failure, Jim Keenen has already addressed the possibilities for that from a strictly gunsmithing point of view.
Here a link to the question I asked over to the S&W forum...
http://smith-wessonforum.com/s-w-ha...on-old-hammer-block-safety.html#post138572406
A fella there referred me to Charles Pate's book "U.S. Handguns of World War II: The Secondary Pistols and Revolvers".
If you have a copy of that take a look at the chapter on The Victory Model. The book also has a entire appendix (Appendix F pages 333-345) on the issue. This features photos and documents covering the inspection, inspection procedures and the source of the problem.
I dug my copy of the book out and will take a look, report back.
As this book came out in 1999 I believe Supica draws from it.
tipoc
http://smith-wessonforum.com/s-w-ha...on-old-hammer-block-safety.html#post138572406
A fella there referred me to Charles Pate's book "U.S. Handguns of World War II: The Secondary Pistols and Revolvers".
If you have a copy of that take a look at the chapter on The Victory Model. The book also has a entire appendix (Appendix F pages 333-345) on the issue. This features photos and documents covering the inspection, inspection procedures and the source of the problem.
I dug my copy of the book out and will take a look, report back.
As this book came out in 1999 I believe Supica draws from it.
tipoc