Transfer bar v. Hammer block

Just your preference for the manufacturer. I am not aware of any makers who offer both systems.

Kevin

Usually, not always, the transfer bar is linked to the trigger and hammer blocks are linked to the safety.

You can imagine scenarios where one my be better than the other, probably.

FWIW, I have heard of only on problem with a transfer bar system and have heard of none with a hammer block system. That failure happened to be on an H&R shotgun though and not a Ruger revolver which is what I presume you are referencing.

Even though that marginal difference is infinite, I would not let it stop me from buying into either type.

The transfer bar has more moving parts and plays a bigger part in the overall trigger pull feel which is part of the reason many say Ruger triggers are not as good as S&Ws.

Both systems have proven themselves over many years.

earlthegoat2 said:

The transfer bar has more moving parts and plays a bigger part in the overall trigger pull feel which is part of the reason many say Ruger triggers are not as good as S&Ws.

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Untrue. Ruger has 1 moving part. S&W has two. The triggers are different for other reasons, some of which is company culture and philosophy behind their designs.

Ruger has had trouble correctly fitting transfer bars, and while they work, they "may" fail - in a safe mode. A correctly fit transfer bar will not fail. I recently adjusted the fit on one of my NM Vaquero revolvers, so I know some issues exist.

Both systems are 99.9% trouble free. Contrast to Uberti Cattleman revolvers "sliding firing pin"...which can fail "unsafe" just by getting dirty, without the shooters knowledge.

Pick any Ruger or Smith based on features other than their inbred safety.

Never really gave it much thought. It's Uberti's new retractable firing pin that grates on my nerves.

Project355 said:

Untrue. Ruger has 1 moving part. S&W has two. The triggers are different for other reasons, some of which is company culture and philosophy behind their designs.

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Ok, for the purpose of discussion and NOT argument I will offer this. The hammer block "part" of S&W revolvers is redundant and as such does not directly contribute to the hammer blocking portion of the safety mechanism. That is my opinion only and is subject to design interpretation. The hammer blocking is done by a bump on the rebound slide interfering with a bump on the hammer. Both of these parts and the rebound slide spring contribute to the hammer block safety. Since the safety aspects are built into other otherwise necessary parts, the S&W could be argued has zero parts contributing to its hammer block safety. However the "hammer block" (that is what it is called on the schematics) is still extant and as such must be included even though it is redundant so the total hammer block safety parts that are only part of blocking the hammer and serve no other function in the operation of the revolver total one. On top of which, if the hammer block safety fails, the gun is still fully functioning. Now, the fact that S&Ws have a redundant safety is a theoretical issue and one that has been hashed out before, so there is that.

You are correct in that Ruger has only one moving part. The transfer bar itself. However, I am in the camp that S&W also only has one. The hammer block itself. The other parts are parts that are otherwise crucial to the operation of the firearm that have slight physical design parameters that create a mechanical hammer block when the trigger is forward.

If the transfer bar fails, the gun is usually rendered useless.

I admit this is cutting thin hairs and I am just saying things as I see them between these two designs. As I said before, I would not hesitate to choose either based on their safety systems alone. I have and would choose Ruger nearly every time for a few other reasons.

I recall extensive discussion of a pre-hammer block S&W dropped on the deck of a ship (from very high up), firing and killing a navy man. The slide-based hammer block mechanism failed (I think a part of the hammer broke off). From this unfortunate event S&W developed the more modern hammer block adding the separate blocking part.

Today I see no issues with either Ruger or S&W style mechanisms. They are both proven systems, for me this renders them effectively identical. Take your pick.

Both systems work very well.

I have heard of Ruger transfer bars failing in SASS as reported by Cowboy Action Shooters. Usually, when I have heard about these failures the gun in question definitely has been modified and usually has had thousands, if not tens of thousands, of rounds fired from it.

Like many things I do believe some of these failures have resulted in near Urban Legend status and had become somewhat of what I like to call “trailer park drama”. You see, one person has a problem and they tell another. The other tells two more and so on and so on until eventually everyone knows someone who knows someone that has had a transfer bar failure.

The one failure I personally know about caused the owner to seek a way to rid himself of the transfer bar system. I eventually did get him to admit that in his exuberance to “slick up” his Vaquero that he “slicked up” the shaft of his transfer bar and in doing so, in my opinion, weakened it. He polished the shaft or bar to ensure it never bound up in the action, thus assuring it broke and bound up his action. Irony.

earlthegoat2 said:

I am in the camp that S&W also only has one. The hammer block itself. The other parts are parts that are otherwise crucial to the operation of the firearm that have slight physical design parameters that create a mechanical hammer block when the trigger is forward.

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Well, the rebound slide would be unnecessary if not for the hammer block. The rebound slide moves the hammer out of the way, the hammer block can slide up between the hammer and frame. They work together.

earlthegoat2 said:

The transfer bar.......plays a bigger part in the overall trigger pull feel which is part of the reason many say Ruger triggers are not as good as S&Ws.

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As you say, splitting hairs. Point is, the transfer bar contributes nada to the behavior of the trigger as experienced by the shooter. If the transfer bar were not there, it would feel the same (and of course not fire).

What I like about both the Smith and Charter/Ruger systems is that they are nearly failsafe. Leave out the transfer bar, or if it breaks... no bang. Leave out the hammer block, the rebound slide covers your butt (but the hammer can fail where it contacts the rebound slide).

As far as Single Actions are concerned, I have had one failure with a Ruger Blackhawk. The transfer bar broke, rendering the gun unusable until replaced. Not this failure occurred after over 5,000 rounds had been fired in the gun.

But the hammer block safety that Ubertis had from the git-go were, in my opinion, about the best of the breed. These allowed the safety to be engaged by placing the hammer in the safety (first) notch. The likelihood of breaking the hammer notch was remote, maybe even never, by dropping the gun on the hammer in that position, as the dasfety br prevented any forward movement of the hammmmmer. Yet it was instantly brought inot action by cocking the hamer.

The "Swiss safe" introduced by the Virginian was the most inane of all, with the two position base pin. Not easily disengaged in emergency.

But of late I've been carrying a Ruger New Model Blackhawk and feel perfectly well armed with its transfer bar.

Bob Wright

I've had one transfer bar break. It was not a Ruger but a US Arms Abilene. It was a defective part and replaced with a Ruger substitution, which actually worked rather well.

Pat Riot said:

I have heard of Ruger transfer bars failing in SASS as reported by Cowboy Action Shooters. Usually, when I have heard about these failures the gun in question definitely has been modified and usually has had thousands, if not tens of thousands, of rounds fired from it.

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Sounds like it is usually has more to do with the incessant dry firing, rather than shooting. Some folks take the statement in Ruger literature that they're "safe to dryfire" to mean that they can do it a million times and nothing will happen.

Ru4real said:

Usually, not always, the transfer bar is linked to the trigger and hammer blocks are linked to the safety.

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Howdy

There is no safety in a revolver. (Yes, there was one S&W model that I am aware of that had a safety, but that was very unusual.) Hammer blocks are actuated by the rebound slide in a S&W revolver.

Let's go through a little bit of history. Originally S&W double action revolvers had no hammer block of any kind inside them. This is a photo of the lockwork of a 38 Military And Police revolver that shipped around 1908. With all double action revolvers the hammer must be withdrawn slightly when the trigger is released. This is so the firing pin does not remain extended into a spent primer, preventing the cylinder from swinging opening when desired. This is the mechanism that S&W adopted about 1905 for all of their double action revolvers. There was a slightly different mechanism from 1899 up until 1905. Anyway, the sliding piece behind the trigger is the Rebound Slide. There is a very strong coil spring inside it, which is partially visible in the slot at the rear of the part. When the trigger is released, the Rebound Slide spring pushes the trigger into the forward position as seen here. The bump on the top of the Rebound Slide wedges the bottom of the hammer up, causing it to retract slightly from the frame and retracting the firing pin back. This allows the cylinder to swing open when wanted. For a number of years, this was felt to be a good enough safety to keep the hammer and firing pin retracted, and a strong enough system that if the hammer were struck, the bump on the top of the Rebound Slide would prevent a round under the hammer from firing. However, over time it was found out that a strong enough blow could snap off the bottom of the hammer, where I drew the red line, or could crush the Rebound Slide (it is hollow after all) enough to allow a round under the hammer to fire.






This is a 38 M&P that left the factory in 1920. It has a hammer block inside. I am not sure exactly when S&W began installing this style hammer block, but I know this revolver left the factory in 1920. Sorry for the dirty rag for a backdrop, I was busy cleaning a lot of old goop out of this old revolver and took the opportunity to snap a photo.






This is the hammer block inside the 1920 38 M&P. This is the first of three different styles of hammer blocks that S&W has installed in their revolvers over the years. If you look closely at the photo above, you will see there is still a bump on top of the Rebound Slide forcing the hammer back. The hammer block is a piece of spring steel installed in a slot in the side plate of the revolver. It has a rectangular tab at the top which projects out towards us. Normally, with the Rebound Slide having forced the hammer slightly back, the tab will sit between the hammer and the frame. I have placed the hand in its position in the side plate for the photo. When the hand rises to rotate the cylinder, it wedges a pin forward, which in turn pulls the hammer block back into its slot, retracting the tab, so the hammer can fall all the way. Because the hammer block is made of spring steel, when the hand is pulled down, the hammer block will spring back into position blocking the hammer from moving all the way forward.






This is the second style of hammer block that S&W installed in their revolvers. Again, I do not know exactly when the change was made. I do know this 38 M&P shipped 1939. This is a simplified version of the earlier design. Again, the hammer block itself is a piece of spring steel, and a tab at the top extends forward into the space between the hammer and the frame. As can be seen in this photo, there is still a bump on top of the rebound slide that has forced the hammer back slightly, creating the space for the tab on the hammer block. I suspect S&W adopted this style of hammer block because it had less parts and would therefor be less expensive to produce than the earlier version. I have no proof of this, but S&W has always striven to drive the cost to manufacture out of their products, and less parts would mean less expense. There is a ramp on the hand. The ramp engages the horizontal tab, a new feature, on the side of the hammer block. When the hand rises, by engaging the horizontal tab, it shoves the hammer block deeper into its slot, withdrawing the upper tab from between the hammer and the frame, allowing the hammer to fall all the way.


This is the style of hammer block that failed in the incident in 1944 aboard a warship, killing a sailor. I have read as much as I can about this. I find no reference to how far the revolver fell, or it if was the sailor's revolver or somebody else's revolver. All that I have been able to find is that a 38 M&P, perhaps a Victory Model, fell to the deck of a warship and discharged, killing a sailor.






S&W had a large contract at the time, providing Victory Model revolvers to the Military. They were ordered by the government to come up with a fix if they wanted to retain their contract. S&W instituted a crash engineering program to get to the bottom of the problem, as well as come up with a new design. Tests showed that a revolver dropped from waist high could indeed discharge if it fell onto its hammer. The best explanation was that hardened cosmoline inside the revolver had prevented the hammer block from springing back to the 'safe position' blocking the hammer. This allowed the hammer to fall all the way, probably breaking the bottom of the hammer off, or perhaps crushing the rebound slide, allowing a round to discharge.

A new design was created within the space of one week.



This is the new design, and it is the same style of hammer block that has been inside every S&W revolver manufactured from 1944 up until today. The hammer block is the long, thin piece sitting at an angle. It rests in a slot in the side plate very similar to where the slot was for the older style hammer blocks. Like the older hammer blocks, there is a tab, hidden in this view, that extends from the surface of the hammer block to block the hammer. Yes, there is still a bump on top of the rebound slide to withdraw the hammer from a spent primer and create a space for the hammer block to rest in. I have placed the hammer block in the position it rests in in its slot in the side plate for this photo. There is a pin mounted in the rebound slide. When the hammer is cocked manually, or if the trigger is pulled double action, as the rebound slide moves back, the pin on the rebound slide pulls the hammer diagonally down, retracting it from the space between the hammer and the frame. When the rebound slide moves forward again, the hammer block slides up again to block the hammer. Yes, all S&W hammer blocks have always been a redundant safety device. Notice in this photo the hammer is not actually contacting the hammer block. It has been retracted enough so that there is space between it and the hammer block. All three S&W hammer blocks have always shared this design feature, they were always a redundant safety device, only put into play if the hammer or rebound slide were damaged. Unfortunately, the earlier design did not stand up to its design purpose when the poop hit the fan. By the way, back during WWII S&W had a recall of all the Victory Models in the field to install the new style of hammer block. Going forward, all the newly manufactured Victory Models had the new style hammer block inside, and instead of just having a V prefix in the serial number, the ones with the new hammer block had a SV prefix.






Transfer Bars:

This is a Ruger New Vaquero completely disassembled. Like all Ruger single action revolvers manufactured since some time in the mid 1970s, it has a transfer bar inside.






The Ruger frame is not conducive to showing the parts in position in the frame, so this is the best I can do to show the relationship between the parts. The transfer bar is the long thin part attached vertically to the trigger. When the hammer is cocked, the trigger spring pivots the trigger back, which also pushes the transfer bar up, positioning it between the hammer and the frame mounted firing pin. When the hammer falls, the transfer bar "transfers" the force of the hammer blow to the firing pin, discharging a round. When the trigger is released, it pulls the transfer bar back down away from the firing pin. In the 'at rest' position of the parts, the upper most surface of the hammer is in contact with the frame. The firing pin clears the recess below the top surface of the hammer, so the hammer cannot physically contact the firing pin.






The transfer bar never rises all the way to completely cover the firing pin. Only about half way, as show in this photo of a Vaquero with the hammer cocked and the transfer bar in the raised position. In order to cover the entire firing pin, the trigger would need more travel in order to raise the T bar that far.






There is a small spring loaded pin in the rear of the cylinder pin of a Ruger single action revolver, it is visible in the exploded view of the Vaquero above. The purpose of this spring is to push the transfer bar back as it rises. If for some reason the spring loaded pin does not push the transfer bar back as it rises, it can jam against the underside of the firing pin, preventing the hammer from being cocked all the way. I discovered this many years ago when heavy loads caused the cylinder pin on my old Blackhawk to jump forward out of engagement with its retaining latch. In this position the spring at the rear of the cylinder pin could not do its job of keeping the transfer bar from jamming under the firing pin, preventing the hammer from going to full cock. There are stronger aftermarket springs available for the cylinder pin latch to prevent this from happening.

Yes, transfer bars can break, rendering the revolver unable to fire, but generally this does not happen very often. I know a few CAS shooters who have broken transfer bars, but they often shoot zillions of rounds per year. Some even keep extra transfer bars handy in case they need one.

There is a condition called Transfer Bar Pinch which can cause this. Easily remedied by an experienced Ruger gunsmith, but not a problem in most cases.

Project355 said:

Well, the rebound slide would be unnecessary if not for the hammer block. The rebound slide moves the hammer out of the way, the hammer block can slide up between the hammer and frame. They work together.

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That is incorrect. Look at my photo of the pre-hammer block 38 M&P from 1908. Originally, in 1899 S&W revolvers had a different mechanism, and there was no rebound slide. But starting in 1905 the design changed and there has always been a rebound slide in all S&W revolvers ever since, even before hammer blocks existed. The rebound slide does more than actuate the hammer block.

StrawHat said:

Just your preference for the manufacturer. I am not aware of any makers who offer both systems.

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Not in the same gun, but Colt offered both types in the same brand.
They kept making Pythons and Detective Specials with hammer blocks for some years after they introduced the Trooper Mk III with transfer bar.

I just knew Driftwood would come along with close clear pictures.
All I can add is that the rebounding hammer is a common safety feature in many, many firearms. My Stevens single barrel shotgun had one. It is also inside where you can't see it on things like "hammerless" double shotguns.

Sorry if this has been mentioned (just got done fixing my broke shower) but I agree with others who have said it's six one and half dozen the other. One exception I can think of though, and it may not be a "thing" in reality--in the Ruger system, the hammer must transfer its energy to the transfer bar, which then strikes the firing pin, whereas in the hammer block design the hammer makes direct contact with the firing pin (or with the primer if using a nose mounted pin).

I say "could be an issue" because out of the box my SRH wouldn't set off CCI small rifle primers firing by trigger cocking. SA mode was no problem, but in that mode there is ever so slightly more compression of the mainspring, which provides more energy to the transfer bar.

My first thought was it had to be that I needed a stronger mainspring, but there were no "extra power" Ruger SRH mainsprings to be found. I started posting my plight on various forums until a gent suggested that I take some material off the hammer nose to enable it to reach farther forward. With the shorter throw of DA mode, the inertia from hammer to transfer bar alone wasn't enough (apparently). When I first heard his advice I thought that didn't sound right because SA mode was 100% with the extra hard rifle primers, why would I need to take more off my hammer nose?

Well with no other options, I did exactly that and at the same time shimmed the hammer (Rugers are notorious for some hammer to frame contact, stock from the box), and it worked like a charm, setting off hard primers DA mode 6 for 6. Anyway, enough of my blather, thanks for your time and everyone have a great day!

CraigC said:

Sounds like it is usually has more to do with the incessant dry firing, rather than shooting. Some folks take the statement in Ruger literature that they're "safe to dryfire" to mean that they can do it a million times and nothing will happen.

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That could very well be the case also.

I very rarely ever Dry-Fire my guns, even with Snap-Caps. Dry firing is like fingernails on a chalkboard to me.

Driftwood Johnson said:

There is a condition called Transfer Bar Pinch which can cause this. Easily remedied by an experienced Ruger gunsmith, but not a problem in most cases.

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Well Howdy to ya too!

I never knew there was a condition with a name! I just called it a bad fitting hammer/transfer bar setup.
Have you noticed that the new Ruger transfer bars have two "fitting pads"? One for firing pin protrusion, the other for the hammer placement when fired? My newer NM Vacquero has the latter, my slightly older (newer to me) NM Birdshead NM Vaquero does not. The newer one was poorly fit. The hammer failed to strike the frame when the trigger was pulled - and the transfer bar was "pinched" as you say, between the firing pin (to the limit of its protrusion pad) and the shelf, or notch on the hammer. Result being.... hammer is hitting the rear upper fitting pad of the transfer bar, and the bar is hitting the frame at the lower front fitting pad.... not a good condition for two reasons. First is overall pinch, second is the way force is applied to the transfer bar. Bound to cause a failure eventually. You can barely feel 'em dray on the hammer/frame when the trigger is released, but you can see the hammer move forward a few .001's when the trigger is released. Sure sign of "pinch". Love that term, never heard it before but it fits. Ideally, there should be just a little bit of slop... when the trigger is pulled, the hammer is down, the transfer bar should have just a very tiny bit of wiggle room between the hammer and frame. No wiggle? Then stress is applied and you get fatigue and parts failure. It doesn't really wiggle, but ya know... just my term for a bit of bias, or "releif" in the mechanism.

My preference - Neither !
Carry on an empty chamber.

NeroM said:

My preference - Neither !
Carry on an empty chamber.

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Absolutely no need to carry on an empty chamber with a modern S&W. Regarding the older ones, I'll bet the cops who carried them every day kept them fully loaded, even before there were hammer blocks inside.

Yup, with a traditional SAA style revolver, best practice is to carry with the hammer down on an empty chamber.

My suspicion is it would probably take more of a blow to the hammer to accidentally discharge an early S&W than a traditional SAA style single action because of the geometry of the parts. The trigger sear on a Colt or clone is very thin and would be easy to snap off. The parts inside a S&W, even an old pre-hammer block one, or one with the early hammer block that failed are much more substantial. It took a cascade of events to get one to discharge accidentally. Dried up cosmoline inside plus being dropped on the hammer.

Pat Riot said:

I very rarely ever Dry-Fire my guns, even with Snap-Caps. Dry firing is like fingernails on a chalkboard to me.

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I don't either. Maybe once or twice but not as regular practice for hours on end. I'd much rather shoot a .22LR than dryfire with a centerfire.