The replacement slide has a smooth breach face. I suspect that there was machining error. My SR1911 was made in June. The thing that surprised me was that the empty case shipped with the gun showed the dent! I can't understand why they would ship the gun in that condition. The shipping and repair cost probably wiped out any profit Ruger made on the gun.
They did right by me and in a reasonable timeframe. Every other Ruger I've owned has been perfect.
Phil
Ruger makes great guns, but their quality control is somewhat lacking. When I received my SR1911, the slide wasn't machined properly to give it enough clearance for the barrel/barrel link ass'y to allow it to come out. I finally forced it out, but I had to do a little file work to get it to go in and out freely like it should.
All my Rugers have required something, even if only extra cleaning to get the factory grit out of it. All, except my LC9. It was delivered perfectly... dripping in oil, but perfectly. However, I got rid of my LC9 because of the trigger. IMO, it's a bad design.
I can easily see how your defect would make it out of Ruger's doors. They just don't inspect them that well. Other new guns I've had include Beretta, Springfield Armory, Sig Sauer, Colt, FNH, Remington, Mossberg and Smith & Wesson. The only other gun I had a factory delivered problem with was my Mossberg 500. The problem was the elevator mechanism wasn't in place and it could not be racked. I figured it out myself and fixed it, but that was the first non-functional gun I've ever bought. It's worked fine ever since.
I'm really hoping that someone at Ruger is paying attention to this. Their quality control is giving their otherwise fine reputation a black eye.
BTW - I just started reloading (finally) and cleaned and inspected all my .45 brass. I don't have any with marks like yours.