I was just kidding with my comments! It's the way things "work" around OR. Hellmut, I'm guessing that by grip length, you are talking about the backstraps? Otherwise, I though they were pretty close to the same length, from the slide to the bottom of the magazine. At any rate, you can't go wrong with the "M Factor", just many of us don't find the price difference to be worth it for what more you get, unless it's something specific like the changeable backstraps.