Hi jam66, as I know, the cylinder gap has only little or no effect for precision. The measurements given by you are great and very closely, I've never seen a Ruger revolver whitch had such a narrow gap. Usually a gap of 0.06 is fine and common, for Ruger revolvers rather more. For good accurracy is more important the alignment of barrel and cylinder and an accurate, tightly throat. The gap affects the velocity only slightly, because when the powder is burning in the cartridge there is so much gas excess that the gap hardly plays a role.