Last night, while practicing with my 649-3 dry firing, the trigger stopped about a 1/4 of the pull through. the gun locked up tight as a drum. I could still open the cylinder, but the trigger would only go that far and there was a hard stop inside. I possed the side to see what had happened and what did I find? See for yourself! This solidifies it for me, MIM is worse than stamped, milled steel. The transfer bar crumbled. I was even pulling hard. everything else looks to be fine except for the one part. I am going to send it back but this would be deadly if I had needed the gun.

Thanks. Confirms my suspicions. Glad that you weren't in danger when it happened.

T-Star

I have a question, had this guns side plate been off before this happened? The reason I ask is this happened to my j frame once. It was entirely my fault. I did not get it back in the gun properly. They must fit in just right in the J's, the slot in the side plate is very narrow. I simply ordered a new one rather than send in the gun. I think they are less than 10 bucks

S*** happens. If I worried about something as unlikely as my transfer bar breaking on my 649, I doubt I'd ever drive anywhere or even be able to make it out my front door.

Considering that there is no pressure on the transfer bar and it just rides happily in its little notch in the revolver sideplate, makes me think it was not assembled properly . . . PS don't let the service department know that you go by DrDremel, it just might void your warranty.

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vim vi repellere licet

Is that a transfer bar? I was thinking a transfer bar "transferred" the force from the hammer to the firing pin, and when it was not there, the force could not be transferred. I may be wrong, but that's what I was thinking. Based on recently taking two guns apart, this looks like a part in mind called the hammer block, which does just the opposite...it keeps the hammer from hitting the firing pin until the trigger is pulled (or the hammer is cocked) which causes the hammer block to slide down. Mine had the groove in the side plate just like this, so I'm confused. Anybody know for sure?

Thanks, B

I never heard of the part called a transfer bar.
What broke was the hammer block.

78 226940000 $5.40 -3 HAMMER BLOCK

Call S&W and order another. I bet they will give it to you for free.

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NRA Benefactor Member

You are correct it is a hammer block, it is a safety device. The gun will still operate without it installed. But don't do it, you drop it on the hammer it will most likely fire. I believe Taurus or Ruger uses the transfer bar technology.

Am I correct that in the Model 442-2, this part is not used? Or did they forget to put one in one of the 442s I recently purchased?

442 has an enclosed hammer, so this part in not needed.

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NRA Benefactor Member

Thanks for the confirmation.
I'm not the smith that some of the regulars are (you included), but I know in the K frames if you do not slide the side plate on correctly over the hammer block, it can be dislodged. If you put the gun back together, s (not smith) w (not wesson) happen.(:

I doubt he hammered his sideplate on.

Regardless of the risks parts like this shouldn't "just break".

I am sorry to be a terminology snob here, but S&W revolvers do not have transfer bars. S&W revolvers have hammer blocks. It is not a trivial matter as a transfer bar does one job and a hammer block does another. Thank you.

Correct, at least as to the last one I looked at with the sideplate off. Since you really never need to do that unless the revolver has been dragged through a mud puddle or otherwise seriously abused or neglected, I have not had occasion to take apart a Centennial for a decade or more. They did not forget to put a hammer block into your Centennial.

All of my S&W revolvers have hammer blocks, but none of them shiny like that one. They're dull stainless in older SS revolvers, and appear to be MIM in the newer ones. The broken block in the photo looks polished.

First, yes it is the hammer block, I used the wrong term sorry. Second, I am very familiar with installing sideplates, the install was fine, no hammering of the sideplate was done to install. The hammer block had been polished with a rag and some flitz. This should in no way compromise the integrity of the part. It is one of 6 of my carry j-frames. As for the name, it came about 20 years ago when I built an AR-15 rec. with a dremel tool and a drill press. It was ugly but it functioned.