The issues with the Model 645 that I am aware of was the screw retained right side safety lever and barrel bushings that were sometimes loosely fit into the slide. I also read that the Model 645's chamber was close to SAAMI minimum dimensions, good for accuracy, might not be good for reloaded ammo using 0.452" diameter bullets.

The other issue was the first run of magazines, which had metal followers that could cause jams and metal floor plates that were held to the magazine body by a small, metal tab. Those floor plates could slide forward and off of the magazine during a fast magazine change.

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VCDL, GOA, NRA