I just bought a low serial number(5 digit) 1951 made Ruger standard (4" barrel) a few days ago. I have two of the old style metal base plate 9rd magazines and two of the newer M-9 new style plastic base plate 9rd mags. I also got a 1971 Ruger standard with with a 4.75" barrel. Both are old enough where the follower button has to be on the right side rather than the left("A-100" frame). I noticed the older 1951 pistol has a non- captive recoil spring assembly yet my 1971 recoil spring is captive where the half-circle end cap on the front cannot slide off. Does anyone know when they changed the spring design? I just discovered this today field stripping the 1951 Ruger. I took both pistols to the range and ran the same ammo through both (Remington 22 thunderbolt and golden bullet). The 1971 Ruger runs fine with both the newer 9rd mags and the older style with the metal baseplates(non-removable) yet when I try them in the 1951 Ruger, it does not want to feed or reliably run with the newer mags. With the old metal base plate mags, the older Ruger runs perfect. Keep in mind I also have the newer mags where the button is on the right for both pistols. Does anyone know why this would be the case? Is there an internal difference between the two guns even though they are the same generation and only 20 years apart in age? Thank you.
