The very first series of the Ruger RST4 pistols, around 2500 guns, went through several changes as the parts for these pistols became available. No pistols were shipped until the whole series of 2500 was finished. Some variations involved:
• Six groove rifling with 14 inch twist rate with some barrels having 5 groove barrels
• Fixed rear sight that was "precision machined" (square version)
• A bolt where the recoil spring guide rod projected through a hole in the top, center of the bolt face.
• The bolt was changed in 1950, and thereafter used the (half-moon) recoil spring assembly support plate. This resulted in less firing pin breakage.
I have "Duncan Long's" book, and would not recommend anyone paying for it, or stealing it. This book is fraught with errors and I ran out of ink in a high-lighter pen denoting what I found. One example: Page 40, top paragraph, "Twists for barrels were 1 turn per 16 inches for early models, with the more accurate 1-in-14, 6 groove rifling being adopted in later pistols". That's completely false.
Turning Ruger Mark pistols into the way they SHOULD perform .
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Last edited by SGW Gunsmith; Today at 11:29 AM.