A few months ago I bought a few used and much abused guns from a retired police officer. One gun, a S&W model 10 was such a boat anchor that it was thrown into the deal as a freebie. Took off the grips & threw it into a bucket of kerosene and let it soak for a week. After much elbow grease, it actually cleaned up somewhat nicely. The bore & cylinder are in excellent condition, as well as the insides. So this gun was shot little but lived a horrible life. Went to shoot it and impact was way off. Front sight leaned way to the left. So by chance I grabbed the barrel and gave it a hard twist, and lo & behold, it turned. I made a washer out of some brass shimstock to go between the barrel & frame. Tightened it in very small increments & shot it, and repeated that until it zeroed to point of impact. Cylinder gap increased to .008, still acceptable. Turns out this old revolver is one hell of a good shooter! And I don't have to worry about scratching it. Good field gun.