S&W K frame internals question
Experts,
I bought a used blued M13-3 3" that was in very good shape recently, and I took it to a "Smith 'smith" to have the action smoothed out a bit. He said that when he cracked it open that the "hammer block" was missing from the inside, all of the other internals were fine and appeared to be untouched.
He guessed that the previous owner opened it up to tinker with it and got overwhelmed, then couldn't figure out how to put it back together and left the hammer block out. (I have since bought one from Numrich and had it installed today, so all is now a-ok.) I am wondering if the removal of the hammer block is something folks do to lighten or improve trigger pulls, or does the "I can't get it to fit so I'll leave it out" explanation make sense.
I bought a used blued M13-3 3" that was in very good shape recently, and I took it to a "Smith 'smith" to have the action smoothed out a bit. He said that when he cracked it open that the "hammer block" was missing from the inside, all of the other internals were fine and appeared to be untouched.
He guessed that the previous owner opened it up to tinker with it and got overwhelmed, then couldn't figure out how to put it back together and left the hammer block out. (I have since bought one from Numrich and had it installed today, so all is now a-ok.) I am wondering if the removal of the hammer block is something folks do to lighten or improve trigger pulls, or does the "I can't get it to fit so I'll leave it out" explanation make sense.
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The hammer block is free-riding, being powered through a stud on the rebound slide which fits into a slot on the lower end of the block. The block itself rides in a slot in the side plate. Drag is negligible.
When reassembling these, it is easiest to properly pre-position the hammer block and then start the side plate by first engaging the slot in the sideplate over the upper end of the hammer block. If the hammer block is at all misaligned with the slot in the side plate, the side plate will not seat.
The hammer block is a fail-safe, to prevent a blow on the hammer from firing the gun. With the hammer down, mating lugs on the top of the rebound slide and on the bottom of the hammer are also in compression against each other, making the gun very difficult to fire with a blow to the hammer (it requires the shearing-off of a major part of the hammer), even with the hammer block removed.
Older S&W's used different hammer block systems, as the design evolved.
IMHO, I've rarely met a new S&W that required any action improvement. Be especially on guard against anyone who cuts or otherwise weakens springs in order to lighten the DA pull, as (depending on the spring involved) this affects trigger return and ignition reliability.0 -
At one time it was usual to remove the hammer block (and bolt spring) from a PPC revolver. But they only make a minute difference in trigger pull and can only matter after a dozen other improvements have been made.
So either Bubba had heard about that (the first part) or maybe you are right and he could not get it back in. It can be a bit tedious to line up. Or maybe he dropped it and could not find it.0 -
As long as the hammer block has no burrs on it, it doesn't have any effect on the trigger pull. I just hit the edges with a stone when doing a trigger job on one. MGM has the right way to get one back in with no problems [;)] 0 -
Thanks guys!
Since nothing looked to be touched inside I figured the Bubba explanation was it, just wanted to check with folks with more S&W time than I'll ever have. At least the screws weren't buggered up from his attempts.
I just had the surfaces lightly touched up, no spring chops or other major stuff. I'm not a fan of over-light trigger pulls, I just like as smooth a pull as I can get with 100% reliability. I watched it get put back together this morning and it did take a bit of wiggling to get the hammer block lined up in the sideplate groove.
Stay safe!0 -
I had a customer who routinely pulled the hammer block from his newly acquired S&W revolvers. 0 -
Don't blame a bubba because he may not have been one. I routinely took out the hammer block when polishing the guts on all of my S & W revolvers. It's a useless addition installed as a CYA by the lawyers. It's not needed so why leave it in there?
JMHO
Ray0 -
Be sure that the mainspring strain screw is fully tightened on the front of the grip frame. This is another trick that bubbas use to lighten the trigger pull and can result in erratic ignition. 0 -
Ya, that screw was checked right before the Hogue grips went on. [:)] How is retirement treating you, Brian. I sure hope all is well (And the old 'Vette is running like I remember it did) 0 -
quote:Originally posted by machine gun moran
The hammer block is free-riding, being powered through a stud on the rebound slide which fits into a slot on the lower end of the block. The block itself rides in a slot in the side plate. Drag is negligible.
When reassembling these, it is easiest to properly pre-position the hammer block and then start the side plate by first engaging the slot in the sideplate over the upper end of the hammer block. If the hammer block is at all misaligned with the slot in the side plate, the side plate will not seat.
The hammer block is a fail-safe, to prevent a blow on the hammer from firing the gun. With the hammer down, mating lugs on the top of the rebound slide and on the bottom of the hammer are also in compression against each other, making the gun very difficult to fire with a blow to the hammer (it requires the shearing-off of a major part of the hammer), even with the hammer block removed.
Older S&W's used different hammer block systems, as the design evolved.
I realize each has the effect of preventing the firing pin from contacting a primer, but my understanding of the hammer block is that it was added to prevent an accidental discharge if one's thumb slipped when lowering the hammer from full cock. The hammer block, riding as it does on the trigger rebound, will interpose itself before the hammer reaches the frame. The hump of the trigger rebound unit is the part of the revolver that prevents the firing pin from striking a primer if the revolver is dropped when the hammer is at rest and keeps the the hammer/firing pin from resting on the frame/primer.
The rebound unit and it's design are essentially unchanged over the past 100 years. It functions on a Model 1917 in the same way as a modern Smith.
There may be more to it than that, I'm only recalling what I've read at the Smith Forum - been a while since I visited.0 -
quote:Originally posted by dfletcher
The hump of the trigger rebound unit is the part of the revolver that prevents the firing pin from striking a primer if the revolver is dropped when the hammer is at rest and keeps the the hammer/firing pin from resting on the frame/primer.True, but apparently this wasn't good enough.
Prior to WWII S&W revolvers were equipped with a non-positive firing pin block that consisted of a spring activated lever pinned into the sideplate.
Early in the war a sailor who was carrying one of these types on-board ship dropped the gun and it landed on the steel two deck levels below. The gun impacted at just the right angle and suffered a parts failure which allowed the gun to discharge. This round struck and killed a sailor who happened to be in the immediate area.
The result was that the Navy put an immediate stop to further delivery of these revolvers. S&W engineers quickly went to work and came up with the excellent positive-safety hammer block system still seen on today's S&W's.0
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