The 620 shoots so well I bought a second one LNIB just incase something happen to my primary. I have a two safes full of old k and n frame Smiths and the 620 is the best shooter in the bunch. The 620, 619 (fixed sight version of a 620) and 2005 520 are some of the most over looked revolvers in the S&W line up.
The 620 and 619 were supposed to replace the 66 and 65 respectively. There were some noted issues with barrel failure where the flange at the muzzle would separate. It happened to one of our forum members who documented with pictures. Mine has at least 8k through it and still going strong. I bought it because they can be had for less than 1/2 what a 357 Mountain Gun commands. Hell, I bought two 620’s for less than Lipsys 357 mountain gun...The 620 and 627-5 were the last of conventional ejector shroud stainless guns Smith made. I had to have both.
My daily shooter 620 is what I use to accuracy test my hand loads and would be one of the last guns I get rid of, if I had to.
I cant really do this as consistantly with my other guns...double action 10 yards.