The most Common S/A Ruger is the Ruger XR3-Red Frame Vaquero/Blackhawk/Single Six Models Old Army and also the Super blackhawks with the 41/2 inch & 6 1/2 inch Barrels lenths. These were made from 1963 to 2004. You'll fine the stamp at the Grip Frame XR3 -Red.  This is also the largest of the S/A grips Ruger Utilizes on there 3 standard Grip Frames.

The Older Model XR-3 Gripframe ( Not Red Frame)  Used on the 3 screw guns made Before 1962. These were the smallest frame grips Ruger made for there S/A's.

The Newest model made from 2005 and has the new Action Locking Feature. This includes the 50th Anniversary Models Also. These Models have serial numbers starting with 510 or 520.

The Newest model 2007 to date New Model Blackhawk & New Model Single Six comes with the Lockable Grip Frame also. Am told the serial numbers end with the letter "L".

The Super Blackhawk Grip Frame with 71/2" & 10" barrels fit only the the Square Trigger Guard Models and models with Shorter Barrels and Rounded Trigger Guards will require a special model grip made by Hogue  HOG-SBR Grips. Hope this Helps In Your Decisions and selections for your Ruger Grips and Frames.

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