I had one of the Colt Defenders, and brass to the forehead was a common problem with them.
I reasoned that shortening the ejector a hair would help, delaying ejection slightly. I took a file to the range with me one day, and tried it, shoot, disassemble, file, assemble, shoot, etc - repeat as required. I found it only took a few thousandths removal from the ejector to fix the problem.
Of course, the Defender was a short slide, and slide velocity was high, which meant it fired the cases out...fast. One day a case came out, turned just right, and the case mouth hit my forehead like a cookie cutter. After I quit cussing I could feel the blood running down, so safed the pistol and went to the rangemaster.
He sure was startled when I walked into his office with a round bleeding hole in my forehead, and asked for a bandaid
