Do fixed firing pins add strength to the lockup vs transfer bar?

TruthTellers · March 14, 2021, 07:13 AM

I was using some empty cases with the dead primers still in them as a snap cap to dry fire a new revolver I have that has the firing pin on the hammer when the thought occurred to me to test the lockup after the hammer falls and see if there's less movement than if there was nothing in the chamber. Sure enough, I did feel a little less play when I had an empty case in the chamber and this was after already hitting those primers a few times deepening the crater.

Now it's got me wondering what affect does the contact between the firing pin and the primer have during actual firing on the overall lockup of the revolver and is there an added strength of a fixed firing pin on the hammer vs that of the transfer bar method where the firing pin is under constant spring pressure?

mehavey · March 14, 2021, 08:31 AM

Unless you have a rebounding hammer, I would offer that lockup of a
hammer/firing-pin-protrusion/primer/case/rim/cylinder "system"
is the same even if you stick a transfer bar in the middle of that mix.

**Aguila Blanca** · March 14, 2021, 11:51 AM

I don't think lock-up after the round has fired means anything. What's important is lock-up and end shake before the round fires -- in other words, is the cylinder/chamber always in the exact same position when the hammer falls.

**44 AMP** · March 14, 2021, 01:52 PM

The term "fixed firing pin" refers to the firing pin used in some open bolt submachine gun designs, where the firing pin is a protrusion machined in the bolt face to serve as a firing pin.

It is "fixed" in the sense that it is not a separate part, and is always sticking out the distance that a regular firing pin travels forward, and so fires the round when the bolt closes.

In revolvers, the term is "mounted on" the hammer (if a separate piece) or just the hammer, or "hammer nose" or firing pin, when it is an integral part of the hammer.

and no, it does not affect the strength of the lockup, either way, hammer or frame mounted.

Driftwood Johnson · March 15, 2021, 11:02 AM

Howdy

As already discussed, the slight reduction of cylinder motion caused by a firing pin trapped in the dent of a fired primer will have no affect on lockup because the bullet will be long gone before the primer has been fully dented.

I do suggest you stop using fired primers as snap caps and instead invest in some actual snap caps.

The purpose of a snap cap is to gently cushion the impact of the firing pin as it comes to rest.

When the hammer slams into the frame as it comes to rest against the frame, the forces of deceleration are astronomical. I worked in the defense industry for many years, and we had instrumentation that could simulate the affects of deceleration, literally what happens when something comes to a sudden stop, for instance falling onto a concrete floor. Acceleration and deceleration are expressed as multiples of the force of gravity. Written as G. You have probably read that when a rocket is launched into orbit astronauts experience about 3Gs, or 3 times the force of gravity. Jet fighter pilots can experience 9 Gs before they pass out from lack of blood to the brain, that is why they typically wear G suits that put pressure on their legs to keep blood from pooling in their legs.

When a hammer slams into the frame of a firearm, the G forces approach infinity. Not 10 Gs, not 100 Gs, it approaches infinity.

With firearms with long thin firing pins, like the firing pin of a S&W revolver, when the hammer comes to a sudden stop against the frame, the tip of the firing pin wants to keep right on going. It does not happen often, but I have seen the tip of such a firing pin snap right off because of the G forces exerted on the narrow cross section of the firing pin.

When using spent primers as snap caps, after a few impacts the primer has been permanently deformed. It can no longer cushion the firing pin because it has taken on the shape of the firing pin at rest. The result is that without the cushioning affect, the tip of the firing pin will want to keep right on going when the hammer comes to a sudden stop.

Snap caps are specifically designed to cushion the firing pin as it comes to rest. Some use a spring, some use a resilient plastic. Snap caps can be home made by removing the primer from the primer pocket and filling it with a resilient substance. Hard rubber erasers, the type used for ink erasers can be used. Regular pencil eraser rubber is too soft. Some folks fill a primer pocket with silicone rubber, but I do not recommend that, silicone rubber is too soft will give way too much when a firing pin strikes it.

I recommend the snap caps made by A-Zoom. The purple ones. I use them in my firearms when I need to drop a hammer.

https://www.lymanproducts.com/brands/a-zoom

TruthTellers · March 16, 2021, 05:07 AM

Driftwood, I'd love to buy some snap caps, but they're not made in .32 S&W short and IDK if the .32 ACP caps would have a thick enough rim and be close enough to the recoil shield to cushion the pin. So, looks like I'll have to make my own.

Would JB weld be an acceptable snap cap or is that too hard? Where could I get these hard rubber erasers?

Nanuk · March 16, 2021, 06:59 AM

JB weld is too hard. The whole point of the snap cap is that it rebounds while the FP hits it.

https://pricecloser.com/product/217/...t+%286+Pack%29

Why is it imperative to use THAT revolver?

You could size some cases and fill the primer holes with silicone? That may work for a while.

TruthTellers · March 16, 2021, 07:24 AM

Quote:

Originally Posted by Nanuk

JB weld is too hard. The whole point of the snap cap is that it rebounds while the FP hits it.

https://pricecloser.com/product/217/...t+%286+Pack%29

Why is it imperative to use THAT revolver?

You could size some cases and fill the primer holes with silicone? That may work for a while.

Who said it was imperative? If I'm gonna buy snap caps, I'd like to be able to use them for ALL my .32 revolvers I currently have or may buy in the future.

Driftwood Johnson · March 16, 2021, 08:25 AM

There is no such thing as 32 S&W Short.

There is 32 S&W, the earlier version, sometimes called 32 S&W Short, and 32 S&W Long. There is also 32 Colt New Police which is identical to 32 S&W Long except the bullet shape is slightly different. 32 S&W Long has the same dimensions as 32 S&W except the case is shorter.

A-Zoom makes snap caps for 32 S&W Long. The purple ones are made of aluminum that has a hard anodize finish on it. If I was you I would buy a set of A-Zoom 32 S&W Long snap caps and cut off the front so they can be chambered in a 32 S&W chamber. The shortened snap caps could also still be used in a 32 S&W Long chamber.

I must be showing my age. Some ball point pens used to come with an eraser on the end, just like on a pencil. The eraser on the ball points was harder than the soft eraser on a pencil. You could also buy erasers that you held in your hand to erase mistakes. You could buy them half and half pencil eraser on one end, ink eraser on the other end. The eraser for pencil was pink, the ink part was a dirty white. I'm sure your local stationary store still sells these. You take a razor blade and cut up the ink eraser to fit into primer pockets of cartridges. Cut it a little bit oversized so when you jam it into the hole it will stay.

No, silicone is too soft. Easy to apply, but it is too soft. JB Weld is too hard. It has to be rubbery.

Radny97 · March 16, 2021, 11:48 AM

Short answer: No

Sent from my iPhone using Tapatalk

Jim Watson · March 16, 2021, 12:47 PM

There is one brand of snap caps with brass "primers", spring loaded to yield under the firing pin.

Your Hollands Royal deLuxe probably came with snap caps having horn inserts.

Bill DeShivs · March 16, 2021, 01:28 PM

Silicone, rubber, erasers, epoxy and such offer literally NO protection to firing pins. The firing pin simply pierces them.

Hard nylon or spring loaded brass snap caps are the only way to go.

243winxb · March 16, 2021, 05:00 PM

Go to Youtube, look for revolver hammer bounce slow motion videos.

March 14, 2021, 07:13 AM	#1
TruthTellers Senior Member Join Date: October 22, 2016 Posts: 3,889	Do fixed firing pins add strength to the lockup vs transfer bar? I was using some empty cases with the dead primers still in them as a snap cap to dry fire a new revolver I have that has the firing pin on the hammer when the thought occurred to me to test the lockup after the hammer falls and see if there's less movement than if there was nothing in the chamber. Sure enough, I did feel a little less play when I had an empty case in the chamber and this was after already hitting those primers a few times deepening the crater. Now it's got me wondering what affect does the contact between the firing pin and the primer have during actual firing on the overall lockup of the revolver and is there an added strength of a fixed firing pin on the hammer vs that of the transfer bar method where the firing pin is under constant spring pressure? __________________ "We always think there's gonna be more time... then it runs out."

March 14, 2021, 11:51 AM	#3
Aguila Blanca Staff Join Date: September 25, 2008 Location: CONUS Posts: 18,477	I don't think lock-up after the round has fired means anything. What's important is lock-up and end shake before the round fires -- in other words, is the cylinder/chamber always in the exact same position when the hammer falls. __________________ NRA Life Member / Certified Instructor NRA Chief RSO / CMP RSO 1911 Certified Armorer Jeepaholic

March 14, 2021, 01:52 PM	#4
44 AMP Staff Join Date: March 11, 2006 Location: Upper US Posts: 28,870	The term "fixed firing pin" refers to the firing pin used in some open bolt submachine gun designs, where the firing pin is a protrusion machined in the bolt face to serve as a firing pin. It is "fixed" in the sense that it is not a separate part, and is always sticking out the distance that a regular firing pin travels forward, and so fires the round when the bolt closes. In revolvers, the term is "mounted on" the hammer (if a separate piece) or just the hammer, or "hammer nose" or firing pin, when it is an integral part of the hammer. and no, it does not affect the strength of the lockup, either way, hammer or frame mounted. __________________ All else being equal (and it almost never is) bigger bullets tend to work better.

March 16, 2021, 05:07 AM	#6
TruthTellers Senior Member Join Date: October 22, 2016 Posts: 3,889	Driftwood, I'd love to buy some snap caps, but they're not made in .32 S&W short and IDK if the .32 ACP caps would have a thick enough rim and be close enough to the recoil shield to cushion the pin. So, looks like I'll have to make my own. Would JB weld be an acceptable snap cap or is that too hard? Where could I get these hard rubber erasers? __________________ "We always think there's gonna be more time... then it runs out."

March 16, 2021, 06:59 AM	#7
Nanuk Senior Member Join Date: January 2, 2005 Location: Where the deer and the antelope roam. Posts: 3,082	JB weld is too hard. The whole point of the snap cap is that it rebounds while the FP hits it. https://pricecloser.com/product/217/...t+%286+Pack%29 Why is it imperative to use THAT revolver? You could size some cases and fill the primer holes with silicone? That may work for a while. __________________ Retired Law Enforcement U. S. Army Veteran Armorer My rifle and pistol are tools, I am the weapon.

March 14, 2021, 08:31 AM	#2
mehavey Senior Member Join Date: June 17, 2010 Location: Virginia Posts: 6,903	Unless you have a rebounding hammer, I would offer that lockup of a hammer/firing-pin-protrusion/primer/case/rim/cylinder "system" is the same even if you stick a transfer bar in the middle of that mix.

March 15, 2021, 11:02 AM	#5
Driftwood Johnson Senior Member Join Date: January 3, 2014 Location: Land of the Pilgrims Posts: 2,033	Howdy As already discussed, the slight reduction of cylinder motion caused by a firing pin trapped in the dent of a fired primer will have no affect on lockup because the bullet will be long gone before the primer has been fully dented. I do suggest you stop using fired primers as snap caps and instead invest in some actual snap caps. The purpose of a snap cap is to gently cushion the impact of the firing pin as it comes to rest. When the hammer slams into the frame as it comes to rest against the frame, the forces of deceleration are astronomical. I worked in the defense industry for many years, and we had instrumentation that could simulate the affects of deceleration, literally what happens when something comes to a sudden stop, for instance falling onto a concrete floor. Acceleration and deceleration are expressed as multiples of the force of gravity. Written as G. You have probably read that when a rocket is launched into orbit astronauts experience about 3Gs, or 3 times the force of gravity. Jet fighter pilots can experience 9 Gs before they pass out from lack of blood to the brain, that is why they typically wear G suits that put pressure on their legs to keep blood from pooling in their legs. When a hammer slams into the frame of a firearm, the G forces approach infinity. Not 10 Gs, not 100 Gs, it approaches infinity. With firearms with long thin firing pins, like the firing pin of a S&W revolver, when the hammer comes to a sudden stop against the frame, the tip of the firing pin wants to keep right on going. It does not happen often, but I have seen the tip of such a firing pin snap right off because of the G forces exerted on the narrow cross section of the firing pin. When using spent primers as snap caps, after a few impacts the primer has been permanently deformed. It can no longer cushion the firing pin because it has taken on the shape of the firing pin at rest. The result is that without the cushioning affect, the tip of the firing pin will want to keep right on going when the hammer comes to a sudden stop. Snap caps are specifically designed to cushion the firing pin as it comes to rest. Some use a spring, some use a resilient plastic. Snap caps can be home made by removing the primer from the primer pocket and filling it with a resilient substance. Hard rubber erasers, the type used for ink erasers can be used. Regular pencil eraser rubber is too soft. Some folks fill a primer pocket with silicone rubber, but I do not recommend that, silicone rubber is too soft will give way too much when a firing pin strikes it. I recommend the snap caps made by A-Zoom. The purple ones. I use them in my firearms when I need to drop a hammer. https://www.lymanproducts.com/brands/a-zoom

March 16, 2021, 08:25 AM	#9
Driftwood Johnson Senior Member Join Date: January 3, 2014 Location: Land of the Pilgrims Posts: 2,033	There is no such thing as 32 S&W Short. There is 32 S&W, the earlier version, sometimes called 32 S&W Short, and 32 S&W Long. There is also 32 Colt New Police which is identical to 32 S&W Long except the bullet shape is slightly different. 32 S&W Long has the same dimensions as 32 S&W except the case is shorter. A-Zoom makes snap caps for 32 S&W Long. The purple ones are made of aluminum that has a hard anodize finish on it. If I was you I would buy a set of A-Zoom 32 S&W Long snap caps and cut off the front so they can be chambered in a 32 S&W chamber. The shortened snap caps could also still be used in a 32 S&W Long chamber. I must be showing my age. Some ball point pens used to come with an eraser on the end, just like on a pencil. The eraser on the ball points was harder than the soft eraser on a pencil. You could also buy erasers that you held in your hand to erase mistakes. You could buy them half and half pencil eraser on one end, ink eraser on the other end. The eraser for pencil was pink, the ink part was a dirty white. I'm sure your local stationary store still sells these. You take a razor blade and cut up the ink eraser to fit into primer pockets of cartridges. Cut it a little bit oversized so when you jam it into the hole it will stay. No, silicone is too soft. Easy to apply, but it is too soft. JB Weld is too hard. It has to be rubbery. Last edited by Driftwood Johnson; March 16, 2021 at 08:32 AM.

March 16, 2021, 11:48 AM	#10
Radny97 Senior Member Join Date: July 8, 2015 Posts: 1,021	Short answer: No Sent from my iPhone using Tapatalk

March 16, 2021, 12:47 PM	#11
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,546	There is one brand of snap caps with brass "primers", spring loaded to yield under the firing pin. Your Hollands Royal deLuxe probably came with snap caps having horn inserts.

March 16, 2021, 01:28 PM	#12
Bill DeShivs Senior Member Join Date: April 7, 2006 Posts: 10,988	Silicone, rubber, erasers, epoxy and such offer literally NO protection to firing pins. The firing pin simply pierces them. Hard nylon or spring loaded brass snap caps are the only way to go. __________________ Bill DeShivs, Master Cutler www.billdeshivs.com

March 16, 2021, 05:00 PM	#13
243winxb Senior Member Join Date: July 26, 2011 Location: USA Posts: 1,730	Go to Youtube, look for revolver hammer bounce slow motion videos.