It would be nice to get some definitive reason for the demise of the 520. Such especially considering the placement of this gun in the S&W lineup. Among a small plethora of adjustable sight 357 models, it the singular fixed sight version. The only one not directly competing with other S&W contemporary adjustable sight models. A 'niche' model. Likely S&W with the specific marketing decision not to hype and quietly drop it. I have a couple of these interesting guns, both NIB. No interest in selling, but would like more definitive S&W perspective history as 'the rest of the story...'
My take