Over the last few months I’ve gotten several emails about light primer strikes — and attendant misfires — with the S&W 686SSR revolver.
The 686SSR is from Smith & Wesson’s “Pro” line, which sits between the semi-customs of the Performance Center and the run-of-the-mill production items. The 686SSR has, among other features, a ‘bossed’ mainspring (which looks suspiciously like a Wolff ‘Power Rib’ spring.) The idea behind the spring design is twofold: first, reduce the spring force at the beginning of tension, making for a trigger which feels more progressive; second, preserve the mainspring arch at reduced spring weight.
The second point probably deserves an explanation. A common method of lightening the hammer spring on a S&W is to shorten the strain screw slightly. When done with a standard flat mainspring the arch is reduced, which often leads to interference between the grip screw and the spring. Having a higher arch, which the ribbed springs provide, allows for full grip screw clearance even at reduced trigger weights.
The problem is that even with the so-called ‘full power’ ribbed springs misfires occasionally happen. This seems to be due to the slightly lessened spring force at the beginning of hammer travel, which is also the end of the hammer travel — when ignition occurs. This is exacerbated by the new California-compliant firing pins that S&W uses, which are shorter and lighter than the old versions. This presumably allows the gun to pass California’s drop test, as I can fathom no other reason for the part to exist.
The short firing pin can easily be replaced by an extra-length version from Cylinder & Slide or Apex Tactical. This usually solves these kinds of ignition issues, though thorough testing needs to be done with any individual gun to verify reliability.
-=[ Grant ]=-
- Posted by Grant Cunningham
- On June 20, 2011