I just picked up a 686 with this spring installed. Single action rivaled a rifle and double action was clean as well. The first day at the range every single action shot went off without a hitch. I would say double action pulls were giving me about a fifty/fifty chance of going off. This was factory ammo. Once safe I re tried the same cartridges in double action and still no go. Again when deemed safe I used the same bullets in single action and they fired. I have installed a factory weight spring but have not been able to get to the range. I know Wolf does not recommend the lighter spring for "critical" applications. Is this common? Thanks, new guy Brian

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DDG-8 "Sine Timore"

Yes, the lighter spring could cause your problem.
I think when you return to range it will be gone.

I had one in my Sp101 and took it out, I had a ton of light primer strikes.

Yes and no. Sometimes the Wolff reduced power mainspring needs a longer strain screw than the std flat S&W spring or the Wolff std power needs.
It's a geometry thing and the "fix" is simple, a longer strain screw. It's 8-32 and socket set screws work well as a strain screw and being grade 8 are a much better piece that the S&W stainless strain screws that are a ***.

In Ruger revolvers, the heavy hammer and trigger return springs are used because the internal pistol parts are minimally machined in the manufacturing process, and the extra spring tension is used to compensate for extra internal friction. If in the process of installing reduced power springs into the Ruger, you remove manufacturing burrs by sanding and polishing the surfaces appropriately and add hammer and trigger springs to remove the slop, then you may have no problem with light primer strikes and gain much nicer trigger performance, more in line with what S&W delivers on their new pistols normally. Kevin Wilson describes here how to improve a SP101 trigger: Ruger SP101 Trigger Job Guide