Reading this one with interest, Just bought a '70 Model 41. Had one about the same vintage years ago that did not run. Tried everything I could even took it to a Gunsmith, no joy. Sold it and bought a High Standard Supermatic. These are REALLY sensitive to magazines. I have two that run perfect, and two that just do not work, even after adjusting with a lip tool. I would try different new magazines see if that helps. Don't really know about the Model 41 mags, but with High Standard mags those that are not factory are junk. I know new Model 41 mags are available from S&W.