I'm assuming it's the same barrel, unless they put the same serial number on a new one. The slip said they adjusted the barrel and sights. It didn't say anything about replacing them.Not really - the barrel has a shoulder on it that fits against the front face of the receiver, with the shank reaching inside to the bolt. The V block pulls that shoulder in tight against the receiver face. If Ruger had left a burr on the shoulder's face, or didn't cut the shoulder square, or left a chip between the shoulder and receiver, that could have canted the barrel over to the point where your rifle was shooting. Did they send it back with the same barrel, or a new one?