Is this the gadget that keeps the cylinder from going too far toward the but and falling in your lap while open? I saw replacement "Frame Lugs" on clearance on the Midwayusa.com website. Educate me please.

On older S&W's the frame lug was a separate piece of round metal riveted to the frame at the bottom rear corner of the cylinder "window".

The gun must be disassembled and a new piece installed and very carefully riveted with a round nose punch to lock it in place, then usually, some additional shaping of the outer surface is often necessary to fit it to a specific gun.

On newer S&W's the frame lug is a long section of the frame behind the cylinder window and is made as part of the frame forging. It's not a separate piece and cannot be replaced.

If your cylinder is falling out, either the lug is missing, in which case there'll be a hole in the frame where it was, or the lug has been altered or badly worn, OR your cylinder assembly is so badly sprung that the cylinder will fall past the lug.

The ones I saw on the Midway site were for model 60 and a few others. I thought that's what it was, thanks for the conformation. I have a victory model that could use one if I could find one and get it fitted but not an emergency though. I thought that lug was machined on all guns. Learn something everyday. Thanks again.

Most any "K" frame cylinder stop will fit, but you need a NEW one and it'll be blued not parked.
Used lugs will usually not rivet properly since they've already been fitted on another gun and the rivet is too short once removed.

I have been able to move the existing lug outward just a hair with a punch. Not a perfect fix of course, but for a gun that isn't shot much or one in less than fine condition, it seems to work.

__________________
John 3:16
WAR EAGLE!

Watch it closely.
The lug will now tend to fall out or rotate. If it turns, you can scar up the cylinder if you open it.