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When did S&W starting using transfer bars and why?

Discussion in 'Handguns: Revolvers' started by JellyJar, Nov 15, 2009.

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  1. JellyJar

    JellyJar Member

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    I have a 3" 629. It uses a transfer bar instead of having the firing pin on the hammer like Smiths I have owned in the past. When did S&W start doing this and why?
     
  2. Oro

    Oro Member

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    Quick answer - 1997. That is when the firing pin went to the frame. I believe that is what you are asking.

    Just to be clear, it isn't a transfer bar. The firing pin is in the frame. The hammer strikes the pin as long as the hammer block isn't in place to block the hammer from reaching it - but the S&W design doesn't employ a bar to "transfer" the hammer energy to the firing pin. That is how a transfer-bar system/safety works.

    Why? Well, only the product designers can answer fully, but the generally accepted thought is that:

    1) It reduces machining steps on the hammer fabrication/fitting and allowed switching to a MIM produced unit that was easier to manufacture.

    2) There was the likely consideration that sometimes the pinned firing pins failed, so it might increase product durability, though in fairness the fp failures in the old style were fairly rare.

    Frame-mounted firing pins are nothing new - they've been around since the 19th century and aren't a quality issue or scary new ground.
     
    Last edited: Nov 16, 2009
  3. 9mmepiphany

    9mmepiphany Moderator

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    you scared me for a moment, until i figured you were refering to the hammer block.

    that's been there for as long as i can remember...and i'm well into my 50's
     
  4. Old Fuff

    Old Fuff Member

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    Smith & Wesson has used frame-mounted firing pins in some models since 1887.

    The current hammer block design originated in 1945, after a Victory Model .38 was dropped from a considerable height and landed on the hardwood deck of a battleship. It discharged and a sailor was killed. The Navy demanded a solution and got it pretty quickly. In addition S&W revolvers (with the exception of those with fully enclosed hammers that don't use the hammer block) have a second independent safety that rebounds (retracts) the hammer and then blocks it so that it can't move forward.
     
  5. Jim K

    Jim K Member

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    The rebound slide was intended more to retract (rebound) the hammer than to act as a hammer block. Retracting the hammer from the primer after firing is a necessity in a side swing revolver. While a top break will open with the firing pin buried in the primer of the last fired round, a side swing revolver won't open unless the hammer is retracted.

    The early S&W hand ejectors (S&W's term for its side swing revolvers, in contrast to the "automatic ejection" of the top breaks) used a rebound lever, powered by a leaf spring. That was changed c. 1906 to the current rebound slide. But S&W concluded that the rebound slide, while it worked as intended, would not stop a blow on the hammer from firing a cartridge, fitted a hammer block c. 1915. The block went through two variations until c. 1945, when the current type was fitted. The previous blocks were spring loaded, which mean they would be ineffective if the spring broke or grease or dirt held the block out of the way. The current block is positive in both directions.

    Jim
     
  6. Slamfire

    Slamfire Member

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    I prefer the hammer mounted firing pin. I like the fact that the firing pin directly impacts the primer. A "direct strike" provides more energy transfer to the primer than a system which hits a transfer bar, then a firing pin, and finally a primer. Energy is always lost in conversions.

    Anyway, to find out why S&W went away from the hammer mounted firing pin I called S&W.

    The gentleman I talked to understood my peevish problem, but he said that it took a unique, special, dedicated machine to cut the slot in the frame. S&W wanted to cut production costs, and the rest is history.
     
  7. Old Fuff

    Old Fuff Member

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    While SlamFire 1 may or may not have a point (transfer-bar safety design revolvers are not generally known to have ignition problems) it should be pointed out that while current S&W revolvers have frame mounted firing pins the hammer still directly hit them.

    In that company's older revolvers the firing pin (called the "hammer nose,") is mounted in a slot so that it can pivot, and held by a rivet. This isn't an exactly rigid mounting, but it obviously works.

    Part of the reason today's manufacturers use frame mounted firing pins is that less metal is removed from the breech face directly behind the cartridge head where it is needed with high pressure loads.
     
  8. Hawk

    Hawk Member

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    I didn't know that.

    Any chance that's the reason for the frame mounted firing pin on the "spare no expense" Python?
     
  9. Old Fuff

    Old Fuff Member

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    Yes indeed. Also they could get more positive ignition while using a lighter mainspring. Notice that other non-magnum Colt revolvers of that era still had hammer-mounted firing pins.
     
  10. Hawk

    Hawk Member

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    Thanks. I am officially "epiphanized"!

    I could never reconcile the notion of "frame mounted firing pin to cut production costs" and its showing up on Colt's flagship.

    Makes perfect sense now.
     
  11. warnerwh

    warnerwh Member

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    I thought Ruger started doing it as a safety factor. With their old model revolvers you only loaded 5 rounds so the hammer/firing pin could rest on an empty chamber. The problem was that if you dropped the gun you could hurt or kill someone. As a matter of fact Ruger will modify any older gun for free to the transfer bar system. Correct me if I'm wrong but I think Ruger started using the transfer bar system in the early seventies.
     
  12. 9mmepiphany

    9mmepiphany Moderator

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    Ruger is still the only company using the transfer bar

    the non-tranfer bar action worked from the since the introduction of the through bore revolver.

    the correct loading ritual is to load one, skip on and load until the first round appeared in the loading gate...then you would lower the hammer on an empty chamber
     
    Last edited: Nov 20, 2009
  13. Old Fuff

    Old Fuff Member

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    Current Taurus revolvers use a transfer bar safety, as did some post-1972 Colt's. Last but not least Beretta Single Action clones and Dan Wesson models did too.

    Ruger didn't invent the transfer bar safety - Iver Johnson did in 1896. Bill's claim to fame was that he was the first to design one that worked in a Colt Single Action style six-gun.
     
  14. 9mmepiphany

    9mmepiphany Moderator

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    i stand corrected...or at least not specific enough...i had the blackhawk conversion in mind when i responded
     
  15. ArmedBear

    ArmedBear Member

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    Sometimes. coincidentally, the more expensive way of doing something isn't necessarily the most durable. I have some of each. Don't give it much thought.:)
     
  16. Oro

    Oro Member

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    I am pretty certain it was 1973 and you are correct.
     
  17. Backpacker33

    Backpacker33 Member

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    I took a quick look at my Anaconda and it has a "transfer bar." That is, a bar must rise and remain there until the hammer falls. There is a cut-out on the face of the hammer that clears the firing pin. The bar must be in place and kept there by holding the trigger back until the hammer falls.
    - Backpacker
     
  18. Dave T

    Dave T Member

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    Because nobody listened to Shakespeare and killed all the lawyers. (LOL)

    Dave
     
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