Unsure of what you mean by a gas ring- that usually describes a ring used in a gas operated automatic firearm- and the 686 is a revolver. Can you repost expanding on your question?- or contact me directly though my message board.
Best left to a factory trained gunsmith
Gas ring changed from yoke to cylinder, 6" bbl introduced, Cylinder counter bore and pinned barrel eliminated, cylinder length changed to 1.62", New yoke retention system/radius stud package.
The Smith and Wesson model 18-2 had the cylinder stop changed,and the trigger guard screw deleted,The model 18-3 had the relocation of the rear sight leaf screw,and the model 18-4 change was the gas ring was moved from the yoke to the cylinder.The model 18-2 change was done in 1962,the model 18-3 in 1967,and the model 18-4 in 1977.
The Model 66-1 was introduced in 1977. The model change was of gas ring from yoke to cylinder. A model 66 ANIB is around $450.00 and EXC is $400.00. The 6" barrel was cataloged in 1978 and was special order only before that year. Hope this helps. Darrell.
S&W did fill a Navy order for signal guns in the very early 1900's. They have also made gas grenade launchers, etc.
because
Heat energy transfers from the gas ring to the spoon handle through conduction. The gas ring heats up the metal base of the spoon, which then conducts heat along the handle. This process continues until the handle reaches the same temperature as the gas ring.
Broken ring and you get compression blow by.
an o ring is a rubber ring that is put around the valve co2 cylinder tank to secure the gas when it is inserted
KWA 1911 sec MEU green gas pistol ------------------------------------------------ swith and Wesson sigma sw40f green gas pistol
William R. Smith has written: 'Oil, gas and the environment'
Broken ring and you get compression blow by.