The first model 686 and other models of the same series extruded the primer around the primer pin and locked up the pistol with hot loads. Very soft foreign made primers were blamed but S&W did a recall anyway to alleviate the problem with a new firing pin and bushing because S&W wanted their guns to work with all ammo that is out there. When the recall work is done, they stamp an 'M' next to the model number in the yoke.

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"He was kinda funny lookin'"