Well, it took a hell of lot of time to figure it out, I'll tell you that much. No kidding, I'll bet I sat there staring into the inards of a Valmet 71 for more than 12 hours over an entire weekend (beer in hand of course) before it finally came to me as to how to pull it off. Once I had the concept in my mind, I had the thing built and running in about 2 hours. The first design would only run about 3 mags and then it would self destruct. The second design would run about 10 mags, and finally on the third go-around I got one to run about 3,000 without a hitch. It's still running in my Galil ARM, but the timing keeps getting later and later, so it will probably need a tune up at about 3,500-4,000 rounds.
I also redesigned my Browning 1919 so it fires off an open bolt instead of the usual closed bolt configuration. No worry with cook-offs anymore.