I know this has been discussed somewhere on the forum. Can somebody direct me to it, please?
They really look almost like drag marks trailing each chamber, and have clearly dented the trailing edge of the chamber.
I have a S&W K-22 Combat Masterpiece revolver, post-war, 3rd Model. “Pre-Model 17.” The rear cylinder face has a lot of those dings in it, and I just want information about that.

Typical cause is someone addicted to rapid fire. While unsightly, if the timing is OK, it doesn't do any real damage but it does devalue the K22. You may have to clean up any dents in the area of the chamber rim recesses to allow cartridges to seat fully.

Thanks, DWalt.
The timing is excellent, the lockwork is tight and rounds seat without problem.
I didn't try REALLY rapid fire, just a steady aim - pull - aim -pull, etc., and I watched carefully between the rear face and the shield to see if the firing pin protruded when it shouldn't, or if it was slow to retract. I saw no issues.
Just a puzzle.

Can't this also be caused by dry firing with empty chambers? Ie no snap caps...

No.

Somehow, the trigger has been pulled when the cylinder is not indexed. One cause is a cylinder that drags badly so that the hand does not force the cylinder into lockup before the trigger is pulled. Powder granules under the extractor and/or unseated rounds in dirty chambers can cause such drag.

I've got a K22 (acquired through a Rock Island auction - so this was the "other" gun ) that has numerous dents in the cylinder from the firing pin. Some are so far out of alignment it made me wonder what a previous owner did to make them....

But the gun's timing is fine, it shoots wonderfully.

--Neill

A dragging cylinder, i.e., poor "carry up", is not the case in this instance. The marks being on the trailing edge of the chambers (left side of the chamber when in battery) indicates the cylinder has, or at one time had, "carry over".

When fired rapidly, the cylinder bolt jumps the cylinder notch and the cyl rotates too far and out of battery causing the firing pin to miss the case rim and dent the cyl face, resulting in a mis-fire. The usual novice reaction is to keep pulling the trigger to get the round to fire, which of course only makes more dents.

If you rapidly cock the hammer for SA shooting, it can do the same thing. Try that but do not pull the trigger and verify if the cyl has rolled past the cyl bolt and is not locked. If not, the problem has been fixed.

A worn bolt and/or it's return spring was most likely the cause.

__________________
Jim
S&WCA #819

Note that the mass of the K-22 cylinder is greater than for a K-38 cylinder. That extra mass makes it a little more prone to carry-over in rapid fire.