Pre-Active Block (1905-1945) S&W Revolvers- What actually happens in a AD/ND event?

[.455_Hunter]

Pre-Active Block (1905-1945) S&W Revolvers- What actually happens in a AD/ND event?

We all know the basic story- During WWII, a fully loaded Navy Victory is dropped and discharges, killing a servicemember. S&W burned the midnight oil and got a positive acting hammer block in production very rapidly, with the same basic design in use to this day.

I know my .32-20 1899 has enough tolerance stack-up to allow the hammer nose to slightly protrude into the primer area if sufficient force is applied to the hammer. It is carried as a 5-shooter when in the field. I believe the action was redesigned by 1905 onward to improve safety and function. My early '30 .38 M&P, Heavy Duty, and Outdoorsman demonstrates no ability for the hammer nose to move forward at rest- I assume the original blocks are working properly.

What actually happens in these AD/ND events:

The spring loaded passive hammer block fails to deploy due to grease, rust, or misfitting?

The force of the impact causes the sear/rebound slide to fracture?

The hammer is allowed to rotate with sufficient energy for the nose to initiate a primer?

Thank you for your thoughts.

 

[Hondo44]

What actually happens in these AD/ND events:

The spring loaded passive hammer block fails to deploy due to grease, rust, or misfitting?

The force of the impact causes the sear/rebound slide to fracture?

The hammer is allowed to rotate with sufficient energy for the nose to initiate a primer?

Thank you for your thoughts.

Basically all three of those had to happen. The key failure however is the hammer block failed to be in position to deny the firing pin access to the primer due to gunk, rust, etc.

 

[Bullet Bob]

As with any historical story, there's usually more than one viewpoint. If you read the gun literature of the late 40's and early 50's, there was some speculation that the seaman was fooling around and had an accidental discharge. "I dropped it and it went off" was as popular then as now.

There of course was a war on, and the military wasn't inclined to look too closely.

 

[DWalt]

Pate's book, "U. S. Handguns of WWII", contains a fairly thorough discussion of that Navy accident and what was done to improve the drop safety.

 

[handejector]

The spring loaded passive hammer block fails to deploy due to grease, rust, or misfitting?

The force of the impact causes the sear/rebound slide to fracture?

Yes, the block would almost certainly have to be stuck in the unblocked position. It supposedly happened on the Navy gun because of grease.


It is not the sear or the rebound slide that breaks. The foot of the hammer resting on the rebound slide breaks off, or, possibly, the hammer stud shears off.

 

[jcelect]

S&W revolverm is

The hammer block is not spring loaded and moves in a channel in the side plate. The force of the trigger rebound slide pushes the trigger forward it also moves the hammer block into a position between the frame and the front face of the hammer below the firing pin. The only mechanical failure that would prevent the movement of the hammer block is the pin in the side of the trigger rebound slide breaking off. Dirt and gunk would also prevent the trigger from resetting! The trigger must reset in order to allow the gun to move a round into firing position and move the hammer reward to set the sear. If the hammer block is left out or on an older gun without the hammer block, 1. a live round must be in the chamber in front of the firing pin bushing, 2. the hammer would be in the fired position, and 3. the hammer is struck by an external force causing the hammer to move forward striking the primer!
A S&W revolver is a marvel of mechanical movements preformed at the proper time and in the proper order to allow a round to be fired!
jcelect

 

[Hondo44]

The gun in question didn’t have the pin in the rebound slide nor the sliding bar hammer block.
There had to be a live round under the hammer.
The hand was at rest and therefore the hand’s integral ramp on its back edge was in position to allow the side plate mounted and spring tensioned hammer block to be under the hammer. But it was frozen in place.
As I recall reported, the gun fell to the deck and discharged, the blow from landing on the hammer overcoming the safety bumps on hammer foot/rebound slide due to fracture of it or hammer stud is unknown to me.

That’s how it could have happened. Or was it horseplay and covered up all these years?

 

[HeloMt]

Based on what I learned in the armorers course...what Lee said. Honestly, I'd be more inclined to go with the horseplay theory.

 

[glowe]

. . . I know my .32-20 1899 has enough tolerance stack-up to allow the hammer nose to slightly protrude into the primer area if sufficient force is applied to the hammer.

If you are seeing "play" in your hammer, something or everything is worn. I just went through 7 of my 1899s and there is not the slightest protrusion of the firing pin when the hammer is at rest and there is zero movement of the hammer. In my mind, it would be very difficult to discharge a round in the chamber unless the force of the drop was great enough to break or bend the mechanism. Very unlikely, but certainly nothing anyone would want to test.

 

[cgt4570]

Even brand new cars off the lot sometimes have failures. It's rare, but it happens.
I'd trust any of my dozens of pre-war Smiths as long as they are handled with normal safe practices. Any firearm can fail if struck in just the wrong way. I've read stories of Glocks of all things going off in holsters in squad cars.

 

[.455_Hunter]

If you are seeing "play" in your hammer, something or everything is worn. I just went through 7 of my 1899s and there is not the slightest protrusion of the firing pin when the hammer is at rest and there is zero movement of the hammer. In my mind, it would be very difficult to discharge a round in the chamber unless the force of the drop was great enough to break or bend the mechanism. Very unlikely, but certainly nothing anyone would want to test.

The focus of this post is the post-1905 guns, but I will discuss. In my 1899, the hammer nose does not protrude at rest. Only if significant hand force is applied to the hammer does it protrude ever so slightly. The gun is not a worn-out loose goose special, so I am assuming that manufacturing variances and tolerance stack-up allow this to occur. Using the gun with 5 rounds in the cylinder is not really a big deal- a 120 year old 6.5" revolver in .32-20 with a somewhat temperamental action is not my first choice for serious social work. As we know, the 1905 redesigned created quite the robust system, so there were reasons why is was done.

 

[Absalom]

Whatever happened specifically during that one fatal incident, horseplay or not, may not be that relevant.

It appears clear from the extensive documentation in Charles Pate‘s book that the Navy‘s concerns over the safety were not just the result of this one event, but that multiple complaints were on record, and the dead sailor was likely just the proverbial straw.

It defies credibility that against the background of 1944-level mortality one accidental death could trigger an extensive testing and redesign process (actually extending the tests to the Colts), as shown in Appendix F of Pate. This was obviously a bigger issue than one guy dropping a gun.