I looked in my stash of S&W parts and low and behold I found a cocking indicator with a spring taped to it. As close as I can measure it is .280" long, outside diameter is .115" and the wire is .011" diameter. Both ends are wound close together for one and a half loops with 6 total loops. (No it is not for sale.)
I hope that this helps.
Have a Happy New Year;
Mike

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Mike
S&WCA #2470