so someone donated a "3" ruger security six (that's the fixed sight model right) to outdoor rec. I got to handle it as we in processed it and it felt surprisingly good. Better than my Smith 2" 64. I haven't shot it yet, but I will.
The kicker is that it was donated because he could not find a buyer. if I had only known.
Only very early Security Sixes had fixed sights. Most were adjustable. You might have a Speed Six.
I need to correct you a bit. The Security-Six was the first model. It had adjustable sights, but fixed sights were introduced several months later. They still had the Security-Six name, but after a very short time, they were re-designated as Service-Six. When they did a round butt version, it was called the Speed-Six. The shortest barrel length was 2 3/4", but there were 3" barrels produced in limited quantities for special LE contracts. After noting those rare exceptions, the most common designations were:
Security-Six; adjustable sights; square butt; 2 3/4", 4", 6" barrel lengths; .357 mag; blued and stainless
Service-Six; fixed sights; square butt; 2 3/4", 4" barrel lengths; .357 mag; blued and stainless
Speed-Six; fixed sights; round butt; 2 3/4", 4" barrel lengths; .357 mag; blued and stainless
There were variants chambered in .38 spl (not .357 mag), .38-200 (British)/38 S&W, and 9mm